THE WASM ANN JO U RN A L OF BIOLO GY

VoL. 12, No. 2 S U~!l\U; R, 1954

The Biology of atripennis flavida LeConte (Coleoptera: Meloidae)'

RICHARD B. SELANDER,' Depm·tntent of Entomol­ ogy, Uni ve1·sity of Illinois, and GEORGE E . BOHART, U.S.D.A., A g1·ic1tltural Resea1·ch Administration, B1t­ rea1t ot Entomology and Plant Q1w1·antine

Inasmuch as practically no biolog·ical data on the New World blister of t he Zonitis Fabricius have been published, it seems appropriate to present the following info rmation con­ cerning one of the common North American species, Z. at1·ipennis (Say) . Previously our knowledge of the biology of the genus has been based on accounts of two Old \Vorld species, Z . pmeusta Fab­ ricius and Z. imnwcula.ta (Olivier ). Among the works dealing with one or both of these species are those of Rossi ( 1792-94), Fabre (1857, 1882, 1886), Giraud (1866 ), Beauregard (1890), Vachal ( 1892), and Cros ( 1921, 1928) . Most of these works pre­ sent descriptions of two or three of the larval instars or their exuviae found in the cells of various bees (see table 1). Apparently none of the authors who have dealt with the development of Zonitis larvae have noticed the complement of larval instars. According to the accounts of Fabre and Beauregard, the imma­ ture stages include a "primary larva," which attaches to the host bee and is carried to the nest, a "secondary larva," which feeds on the provisioned material in the bee cell or cells, a " pseudo­ chrysalid" resting stage, a "third larva," and a pupa. However, in discussing Z. immaculata, Cros (1928) indicated that the "secondary larva" actually includes the second, third,

Received for publication November 24, 1952 . 1. Acknowledgments are made to W. P. N ye, who, in association with the junior author, prepared the photog raphs il lustrating this paper, and to C. D . Michener, wh o kindly checked over and brought up to date the generic assignments of the species of bees listed in table 1. 2. A National Science Foundation fellowship partially supported the senior author's par- ticipation in this study ; the University of Utah and the I ll inois Natural History Sur vey sup­ plied facilities for work. [ 227] 228 THE W ASMANN JOURNAL OF BIOLOGY, Vor.. 12, 1954

and fourth larval instars. Furthermore, it now appears that the "third larva" in these species consists of more than a single instar.

DIS'l'RIBU'l'IOK OF ZON I'l'IS A'l'RIPENNIS Zonitis at-ripennis is widely distributed in the western United States. It is represented by two subspecies, which were univer­ sally treated in the literature as separate species prior to the

TABLJ<: 1 Lm·val hosts of some speci es ot Zonitis

Zonitis -~1Jecies Author··ity Z. ctt1"i1J ennis f/a.v ida LeConte Nornia m.. rnelander·i Cockerell...... New r ecord Z. immaculata (Olivier) Anthidiurn rnanicatum (Linnaeus) ( n ...... Cros, 1928 Anthocopa longispina (Perez) ...... Cros, 1928 H oplitis (1) cavigena ( P e•·ez) ...... Cros, 1928 Hoplitis nwr-awitzi (Gers taecker ) .. Cros, 1928 Hoplitis l1"iclentata (Dufour and P erris) ...... Giraud, 1866; Fabre, 1882 I cter·anthidi1tm ( t ) bellicos1tm (Lepeletier ) ...... Fabre, 1886; Beauregard, 1890 I ct er-anthiclium discoidale (Latreille) ( f) ...... Cros, 1928 Megachile (Chctli codoma) rmtr·ar-ia (Retzius) ...... Rossi, 1792-94 Osrnia 1)S e1tdoauntlenta Dours ...... Cros, 1928 Osmia sp. (0. latr·eill ei (Spinola) or 0. tr·icor·nis Latreille ) Fabre, 1882 Osrnia spp ...... Cros, 1928 Z. 7J r-aeusta Fabricius A nthidimn sp...... Cros, 1928 Anthocopa longispina. (Perez) .. Cros, 1928 AnthoC01Ja, saunder·si (Va cha !) .. Vacha!, 1892; Cros, 1928 l cter·anthidium 0 ) bellicos·urn ( Lepeletier ) ...... F a bre, 1886 Megachile se1'iccms Fonscolombe...... Fabre, 1886; Vacha!, 1892 111egachile sp...... Cros, 1928 Osn·tia 1J seudoaw·ulenta Dours...... Cros, 1928 Osrnia sp...... Cros, 1928 Pa.nmthidielhtrn lit1tr-at1trn sca1mlar-e (Latreille) Fabre, 1886 Z. sp. Co llet es daviesamus var. signat1tS Verhoeff...... Beauregard. 1890

Figure 1. Nornia rn. rnela.nde·l"i Cockerell. N esting s ite, showing wind­ blown chimneys, salt c rust of undisturbed s urface, and t ypical vegeta· tion.

Figure 2. Nomia m. m elancler··i Cockerell. Adult female. BIOLOGY OF ZONITIS-SELANDER Al'W BOHART 229

2 230 THE WASMANN JOURNAL OF BIOLOGY, Vor.. 12, 1954 appearance of a recent paper by McSwain (1951 ). According to available records, the range of the subspecies Zonitis atripennis fiavida LeConte extends from the Pacific Coast eastward to cen­ tral Colorado and New Mexico, where it meets that of the nomi­ nate subspecies, which ranges still farther eastward, onto the Great Plains. The eastern limits of the species are unknown to us, but we have one record as far east as \Vest Virginia. 'rhe western subspecies, Z . a. fia vida, is relatively common throughout Utah, where the present studies were undertaken. In the desert areas near Delta and Fillmore, Millard County, it has been frequently encountered as a parasite in the nests of the halictid bee Nomia melande1·i rnelanderi Cockerell. The following account of the biology of this bee may be helpful in explaining the details of this parasitism.

BIOLOGY OF N OMIA l\1 . MELANDER!

This bee (fi gure 2) nests gregariously, often in great concen­ tration, in alkaline desert regions, selecting areas where the sub­ surface soil remains soft and moist throughout the summer months. Typically, a single nest consists of a burrow about one foot in depth, which is irregularly branched to form small aggre­ gates of cells (fi gure 3). The total number of cells per burrow varies from twelve to twenty. The female bee hardens the wall of the main burrow by tamping with her abdomen. The walls of the cells are carefully shaped and smoothed and then polished by t he addition of a secretion produced by the female bee. When the nest is first excavated, the entrance is surrounded by a low mound of soil , but within a few days the excavated soil is generally scattered by the wind so that the hardened wall of the burrow forms a short chimney at the surface (fi gure 1). Each cell is provisioned with a soft ball of honey and pollen, upon which a single elongate egg is deposited before the cell entrance is sealed. According to observations of nests in Washington, southern Idaho, and Cache Valley, in northern Utah, N. m. rn elanderi has but one generation a year. In these areas, as in the more southern Millard County, Utah, adults begin emerging in early July, and fema les may be found provisioning their nests throughout that month and during most of August. During late August and early Septe mh er the larvae complete their feeding and reach the over- BIOLOGY OF ZONITIS-SELANDER AND BOHART 231 wintering prepupal stage. In the Millard County area, however, it appears that part of the larvae produced by overwintering bees complete their development during the same summer and emerge during the last half of August, thus forming a small second gener­ ation. Th e progeny of this late emerging generation overwinter in the usual manner, as prepupae. Since only a small proportion of the larvae produced by the first generation complete their develop­ ment in this manner, it appears that, at least in the Millard County area, the second generation adults develop from those larvae produced by the earliest emerging adults of the first gen­ eration or possibly from those larvae which occupy cells relatively near the surface of the soil. Farther to the south, where the first emergence of adults is much earlier, two generations a year of N. m. melande1·i may be the rule rath~r than the exception. The developmental stages of this bee are shown in figures 4 and 7 (see also Bohart, 1947) . In Utah Nomia m. melande·ri is an important pollinator of al­ falfa. Other introduced plants which are visited include yellow and white sweetclover, Russian-thistle (Salsola kali var. tenui­ folia Tausch), bindweed (Convolvulus m·vensis Linnaeus), alfalfa dodders ( Cuscuta spp.), and tamarisk ( Tamarix gallica Lin­ naeus). Alfalfa, white sweetclover, and Russian-thistle provide all but a small percentage of the pollen gathered in the cultivated areas. Late in the season, when these sources become scarce, rabbitbrush ( Ch1·ysothamnus nauseosus (Pallas)), hawksbeard ( C·repis g7-

J_;IFE HISTORY OF ZONITIS ATRIPENNIS FLAVIDA

Although Zonitis at1·ipennis fiavida has not been completely reared under laboratory conditions, it has been possible to outline its life history through partial rearing experiments, coupled with numerous observations in the field . As in the case of most other 232 THE WASMANN JOURNAL OF BIOLOGY, VoL. 12, 1954 species of which have been studied, the winter is passed as a fifth larval instar, enclosed in a capsule formed by the exuviae of the fou rth instar. J_;ATER LARVAL DEVELOPMENT AN D P UPA TION. 'l'he fifth instar (fi gures 6, 11 ) is dark orange in color, moderately depressed and slightly curved in form, and from 10 to 11 millimeters in length. The antennae, mouthparts, and legs are vestigial. The epicranial suture is obsolete. The integument, which is of hard texture, is covered with minute, wart-like projections, each bearing a single short seta. Spiracles are present on the mesothorax and first seven abdominal segments; they are subequal in diameter, elevated, and dorsal in position. The body possesses two strongly elevated ridges laterall y, the lower ridge on a level with the legs, and con­ fined to the abdomen, the upper ridge located about halfway be­ tween the lower ridge and the level of the spiracles, and extending the complete length of the body. In general appearance the fi fth instar resembles more the homologous instars of JIo1·nia minuti­ pennis Riley and scutellwris LeConte (see Linsley

Figure 3. Nomia 'ln. melandeTi Cockerell. Vertical section of burrow, showing areas of branching. Figure 4. Nom i a m. melanderi Cockerell. Vertical section of cells, showing ( 4a) eggs in place on pollen balls (lateral and dorsal aspect ) a nd ( 4b) developing larva and fully fed larva. BIOLOGY OF ZONITIS-SELANDER AND BOHART 233

and McSwain, 1942a, 1942b, 1952) than those of Zonitis pmeusta and Z. irnrnaculata, which have been described and figured as cylindrical and pupariform.

Figure 5. Zonitis atl"ipennis flavida LeConte. Egg mass on floret of Cleome serrulata Pursh. (Alignment of eggs disturbed in handling.) Figure 6. Zonitis atripennis ttavida LeConte. Pupa, fifth larval instar, and exuviae of fourth larval instar. 234 THE WASMANN JOURNAL OF BIOLOGY, VoL. 12, 1954

In the following summer the fifth instar moults to the sixth, now enclosed by the exuviae of the fourth and fi fth instars. Ap­ parently the fifth and sixth instars each work the exuviae of the preceding instar backward during the moult, as the tracheal lin­ ing of these exuviae run forward from the spiracular openings. Judging from the exuviae, the sixth instar is pale in color, grub-like in form, and provided with relatively well developed appendages. The epicranial suture is absent. The antennae are three-segmented. The mandibles are well developed and apically acute. The maxillae and labium are large and robust, but they have vestigial palpi. The legs are short, conical, and without claws. Of course, no food is taken by this instar, since it is com­ pletely enclosed in the exuvial capsule. Apparently the sixth stadium is of short duration. Upon pupation the exuviae of the sixth instar are pushed back­ ward into a compact mass, which adheres weakly to the end of the abdomen of the pupa (figure 6) . At the completion of the pupal stage the adult rips open the posterior end of the €xuvial capsule by means of leg movements, and emerges by back­ ing out, the pupal exuviae being reduced to fragments in the process. In the case of Zonitis pmeusta and Z. immaculata it has been repeatedly stated in the literature that the exuviae of the "third \ larva" (sixth instar) become adherent to that of the fifth instar and are not completely shed at the time of the moult, a condition also recorded in the genus N emognatha. In several species of the latter genus, including N. hu1·di MacSwain and N. scutellaris, Linsley and MacSwain (1942a, 1952) have found it involved with the occurrence of a seventh larval instar, in which case the ·exuviae of the sixth instar enter into the formation of the capsule with the exuviae of the fourth and fifth instars. The occurrence {)f the seventh instar is reported as variable in N. scutellm·is. In the case of Zonitis atripennis fia vida neither the occurrence {)f a seventh larval instar nor the encapsulation of the pupa by the exuviae of the sixth instar has been observed. Although the accounts of the two Old 'Vorld species of Zonitis mention only the presence of a "third larva" following the fifth instar and pre­ ceding the pupal stage, there are indications that this "larva" actually includes two instars. Fabre ( 1882) and Cros ( 1928), in discussing Z. immaculata and Z. praeusta, respectively, men- BIOLOGY OF ZONITIS-SELANDER AND BOHART 235 tioned finding a small mass of exuvial debris in the bottom of exuvial capsules of larvae which had completed development, and both authors suggested that the mass represented the exuviae of the pupa. Since the pupal exuviae in all species of Nemognathi­ nae which we have studied are never pushed backward into a mass, it is likely that the exuviae to which Fabre and Cros r e­ ferred were actually those of seventh larval instars. SEASONA L OccuRRENCE OF ADULTS. Adults of Z. a. fia vida have been collected in Utah from June 18 to September 1. Records in June and early July are exceptional, however , and it appears that the period of greatest abundance of adults is from mid-July to late August. At one of the nesting sites of Nomia near Delta, on July 20, 1951, both fifth larval instars and pupae were found in cells constructed the previous year, while pupae were encountered as late as July 27. Individuals collected as fifth instars fr·om cells in early July, 1951, and reared in the laboratory, completed development and emerged as adults in mid-August. Teneral adults were found in cells on August 28, 1949, at Delta. Farther· to the south the emergence period is earlier. \Ve have examined adults collected at Gonzales Bay, Baja California, in April. As will be noted, the period of emergence of Z. a. fia vida cor­ responds closely to that of N. m. melanderi, although the period of gr eatest abundance of adults of the former species occurs slightly later than that of Nomia. It is therefore not surprising to find that, in Millard County, the nests of the second generation of N. m. melande1·i, which are provisioned in late August and early September, have a much higher degree of parasitism than those produced by the first generation. HosT PLANTS AND FEEDING HABITS OF ADULTS. Cockerell (1898, 1901 ) and Fall and Cockerell (1907 ) Tecorded nominate Z. a,tripennis from Cleome in New Mexico. Since all of our col­ lection records of adults of Z. a. fia vida are from Cleome also, it appears that the species is limited to plants of this genus. The adults of Z. a. fiavida are similar in color to the yellow florets of C. lutea, but they stand out conspicuously against the purple florets of C. sen·ulata. The galeae of the maxillae of the adult beetles are not produced, as in a number of species of Nemognathiuae which feed on nectar, but they are provided with brushes of long setae, and it is possible 236 THE W ASMANN JOURNAL OF BIOLOGY, VoL. 12, 1954 that some nectar adheres to these and is ingested. In any event, observations in the laboratory indicate that the principal food is pollen. In several species of N emognatha and Zonitis which have been studied much of the pollen eaten is that which adheres to the pubescence of the body and which is subsequently cleaned off and transferred to the mouthparts by means of the legs. Adults of Z. a. fia vida., however, are not particularly densely pubescent, and since they do not commonly contact the anthers of Cleome with their bodies, little pollen collects upon them. Rather, the beetles employ the prothoracic legs to bend down the long stamens of Cl eome, and ingest the pollen directly from the anthers. MATING AND OviPOSI'l'ION. Copulation takes place with little preliminary courtship. In attempting to contact the genital open­ ing the male may stroke the head and basal antenna! segments of the female with his antennae, but he does not use the antennae to aid in maintaining his position, as do males of species of Lytta and 111 elo e. Copulation lasts from a few seconds to several min­ utes. A single male may copulate with several females, while a female generally accepts more than one male. Oviposition takes place immediately after copulation. Eggs are deposited in small masses, consisting of several layers, on the stems, florets, and pods of Cleome (fi gure 5) . A cotmt of two separate egg masses obtained in the laboratory gave values of 314 and 514. It is not known whether a female deposits more than one egg mass. Individual eggs are pale lemon yellow in color and rather small in comparison to the eggs of species of N emog­ natha of similar body size. They are aligned in the mass with their long axes perpendicular to the substratum. EARLY LARVAL DEVELOPME NT. E ggs deposited August 26 and 27 hatched in 14 to 17 days ( Septem her 10 to 12 ) wh en incubated at room temperatures. Larvae began leaving the egg· masses one day after hatching was first observed. Prior to this they remained quiescent among the egg shells and unhatched eggs. It was noted that on flowering stems of Cleome kept in the laboratory newly hatched larvae crawled around on the pods and florets, often penetrating into the nectaries, but that they did not ascend the stamens to the anthers. The first instar (figure 9 ) is light brown in color, except for the areas surrounding t.he ocelli, which are nearly black. The bod.'- BIOLOGY OF ZONITIS-SELANDER ANIJ BOHART 237 length averages two-thirds of a millimeter. The epicranial suture is obsolete. The antennae and maxillary palpi are three-seg­ mented, the labial palpi two-segmented. The mandibles each bear three large dentes along the mesal margin. The dorsal dehiscent suture is complete on the meso- and metathorax, obsolete on the prothorax. The abdomen is nine-segmented. Spiracles are present on the mesothorax and first eight abdominal segments; they are snbventral in position, except for those of the eighth abdominal segment, each of which is located dorsally at the apex of a slender process of the tergite. The spiracles of the mesothorax and first abdominal segment are considerably larger in diameter than the rest. The descriptions of the first instar larvae of Z. praeusta and Z. immaculata agree in most details with the first instar of Z. a. fi(tvid(t.

Figure 7. Vertical section of Nomia cell series, showing (top a nd bottom rows) variously developed pupae, ( middle row, left) diseased prepupa a nd normal prepupa, and (middle row, extreme right) adult fe male of N. m. melande1'i Cockerell, and (middle row, center) two fifth larva l instars of Zonitis at1'i7Jennis flavida LeConte, each enclosed in exuviae of fourth instar. Figure 8. Zoniti.s at1"ipennis flavida LeConte. Adult. 238 THE WAS MANN JOURNAL OF BIOLOGY, VoL. 12, 1954

The first instar larvae undoubtedly gain access to the nests of their hosts by attaching to adult bees visiting Cleome. A single first instar was obtained from the metathoracic tibia of a female N. m. melanderi coll ected at Lynndyl, Millard County, Utah. The larvae exhibit strong positive phototaxis, and otherwise show the usual nemognathine activity pattern (see Linsley and McSwain's (1942b) account of the first instar larvae of Ifornia minutipennis occidenta.lis Linsley). When walking, at least when the footing is insecure, the larvae spin a thin silken thread from the anal region, which is laid down as they progress. If their footing is lost they r egain their positions by means of rapid grasp­ ing movements of the legs and bending of the body. It has not been determined whether the larvae actuall y grasp the thread and climb back upon it, or if the thread is pulled back into the abdomen. The tip of the abdomen, which acts as a suction disk and pseudopod, is always the first part of the body to reach the regained position. Since no remnants of bee larvae have been found in cells infested with Z. a. fia vida, it seems probable that the first food of the first instar consists of the egg of its host, as in other species of Nemognathinae. Later, possibly not until it reaches the second stadium, the larva begins feeding on the pollen and honey pro­ visioned in the cell which it occupies. Feeding continues through the fourth stadium, at the end of which the larva becomes quies­ cent and moults to form the non-feeding fifth instar mentioned earlier. According to Cros (1928) the larvae of Z . praeusta and Z. immaculata require the contents of two cells for development, the individual larva feeding first on the provisioned contents of one cell and then penetrating into another where it feeds on the bee larva contained within it. 3 However, since cells in which fifth instars, pupae, and adults of Z. a. fia vida have been found have in all cases lacked any evidence of openings, it appears that the contents of one cell are sufficient for complete development, and that the original cell is not vacated by an individual until it emerges as an adult beetle. This conclusion is in harmony with

3. This condition was also reported for a larva of another species of Nemognathinae, Z onitoschema pallida (Fabricius), as a parasite of Megachile sculpturalis Smith, in Japan (Iwata, 1933). BIOLOGY OF ZONITIS-SELANDER AND BOHART 239

the statement of Linsley and MacSwain (1952 ) concerning the development of larvae of Nemognatha. The second and third instars have not been obtained, and the fourth instar is known only from exuviae. Because the exuviae of the fourth instar remain intact when moulted, the general fea­ tures of the larva can be readily ascertained. The exuviae of the fourth instar (figures 6, 10) are robust and grub-like, with the legs well developed and possessing small claws. The epicranial suture is obsolete, as in the first, fifth, and sixth instars. The labrum is distinct. The antennae are three-seg­ mented. The well developed mandibles are denticulate along the mesal margin. The maxillary palpi are three-segmented, the labial palpi being reduced to knobs. Spiracles are present on the mesothorax and first seven abdominal segments; they are ex­ tremely large in diameter, and, as in the fifth instar, dorsal in position. The spiracles of the abdomen are progressively smaller in diameter posteriorly. Since the exuviae are colorless and thin, the enclosed fifth instar is readily visible.

EXTENT OF THE pARASITISM. In the areas studied, the infesta­ tion of Zonitis at1·ipennis fia vida in Nomia m. melanderi cells is somewhat less than one percent. This relatively low figure is prob­ ably at least partially the result of the fact that in these areas there is a great abundance of alfalfa and sweetclover, plants which are highly attractive to N. m. melanderi and upon which Z. a. fia vida does not occur. In uncultivated regions, where Cleome may be more competitive for the attention of the bee, the degree of parasitism by this beetle is probably much higher. Examinations of Nomia nests in Washington, Idaho, and Cache Valley, northern Utah, have failed to reveal Z . a. fia vida as a parasite, although it is definitely known that the beetle occurs in the latter two areas. An explanation of this situation may be that Cleome was not present within the flight range of the bees, a dis­ tance of about five miles. Although it was not determined if this were so at the time the nests were examined, the fact that the dis­ tribution of Cleome is spotty adds support to this supposition. In any event, it is quite firmly established that the presence of Cleome in the vicinity of the nesting site is an essential factor in the parasitic relationships of Z . a. fia vida and N. 1n. melanderi. From this it is obvious that, in the event that parasitism of 240 THE WASMANN JOURNAL OF BIOLOGY, VoL. 12, 1954

N omia bees by this beetle becomes serious in alfalfa seed crop areas, the destruction of Cleome plants near the nesting site would be an effective control measure. Since a number of species of bees visit Cleome, there is a pos­ sibility that Nomia melande·ri is not the only host of Zonitis a.

I

10

11

Figure 9. Zonitis a.t?"ip ennis ttav icla LeConte. First larval instar, dorsal aspect. Figure 10. Zonitis at1'i11 ennis ttav ida LeConte. Fourth larval instar exuviae, aorsal aspect of head. Figure 11. Zonitis at?"ipennis ttcw idct LeConte. Fifth larval instar, lateral aspect of head. BIOLOGY OF ZONITIS- SELANDER ANn BOHART 241 fia vidct. However, the solitary bees most abundant on Cleorne, species of Per-dita, Lasioglossum, and Nornadopsis, are too small to serve as hosts, unless, as reported for other species of Zonitis, the larvae of Z. a. fia vida are capabl e of utilizing the contents of more than on e cell as food. In addition, these bees visit Cleorne primaril y for pollen, rarely touching parts of the florets other than the stamens. Since our observations indicate that the first instar lar vae of Zonitis a. fi avida do not freq uent these structures, it may be that t he larvae have little opportunity to contact these bees in any numbers. In addition to Nomi(t, common Cleome visitors of larger body size include A nthophom u. ur-bctn(t Cresson , 111 elissodes obliqua Sa ~' , two undetermined species of jJJelissodes, and Agapostemon cockeTelli Crawford. The first species seems to be the best possi­ bility as a Zonitis host, since it is the only one in which both sexes are known to visit the plants. The females readily collect both pollen and nectar from Cleome. It is interesting to note that in southern California and Baja California Zonitis (t. jl(tvida is within the range of, and probably parasitizes, N omi(t rn elande1·i peninsulm·is Cockerell. Further­ more, since N . melanderi has been recorded only as far east as Colorado, it is highly probable that a different larval host is in­ volved within the range of nominate Z. at1·ipennis.

SUMMARY OF 'l'HE LIFE HISTORY OF ZONI'l'IS

On the basis of our present knowledge, the biology of the genus Z onitis is essentially the same as that of the genus N emognath(t. In summary, the general life history of the species of Zonitis which have been studied is as follows : Eggs are deposited on flowers or flowering stems, the first instar larvae attaching to visiting bees in order to reach the cells in which development takes place. The first four larval instars feed on the provisioned contents of a single cell ( Z. a. fi a·vid(t), or the 'provisioned con tents of one cell and the bee larva of another ( Z . p·raeu.st(t and Z. immaculcda), the egg of the host bee being destroyed before the provisioned material is attacked. The exuviae of the fourth instar are not completely shed at the moult, but encapsulate the non-feeding fifth instar. The fifth instar merely overwinters, or may persist for two or more years before 242 THE WASMANN JOURNAL OF BIOLOGY, Vol. . 12, 1954 moulting. During the moult the exuviae of the fifth instar also encapsulate the inactive sixth instar. Pupation follows shortly (Z. a. fiavida ) or a seventh larval instar intervenes (Z. pmeusta and Z. immaculata). In the latter case the exuviae of the sixth instar join in the formation of the exuvial capsule. In either case the exuviae of the last larval instar are completely shed during the moult and are pushed to the posterior end of the cap­ sule. Upon emerging the adult beetles gather on :flowers, where they feed on pollen and possibly nectar, and upon which they subsequently mate.

LITERATURE CITED

BEAUREGARD , H . 1890. Les insectes vesicants. Bailliere et Cie, Paris. xiv + 544 pp., 19 pis., 44 text figs.

BOHART, G. E. 1947. Wild bees in relation to alfalfa pollination. Farm and Home Science, Utah Agricultural Experiment Station, 8 ( 4) : 13-14, 6 figs.

COCKERELL, T. D. A. 1898. Life-zones in New Mexico. II. The zonal distribution of Cole· optera. New Mexico Agricultural Experiment Station, Bulle­ tin 28:137-179. 1901. Flower and records from New Mexico. Entomological News, 12(2) :38-43. CROs, A. 1921. Notes sur les larves primaires des Meloidae avec indication de la1·ves nouvelles (2• serie) . Annales de Ia Societe En­ tomologique de France, 90:133-155. 1928. t;tudes biologiques sur les Zonitis ( Meloidae). EncyclopMie Entomologique, Serle B, Coleoptera, 3: 7-34, 1 pl.

FADRE, J. H . 1857. Memoire sur l'hypermetamorphose et les moeurs des Meloldes. Annales des Sciences Naturelles, Zoologie, ( 4) 7: 299-365,' pl. 17, figs. 1-8. 1882. Nouveaux souvenirs entomologiques. Delagrave, Pa1·is. 349 pp. [Souvenirs entomologiques, Deuxieme serie. in later editions.] 1886. Souvenirs entomologiques. Troisieme serie. Delagmve, Paris. 433 pp., 9 text figs. BIOLOGY OF ZONITIS-SELANDER AND BOHART 243

FALL, H. C., and T. D. A. CocKEilELL 1907. The Coleoptera of New Mexico. Transactions of the American Entomological Society, 33:145-272.

GIRAUD, J . 1866. Memoire sur les insectes qui habitent Ies tiges seches de Ia ronce. Annales de Ia Societe Entomologiques de France, ( 4) 6: 433-500.

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LINSLEY , E. G., and J . W. MA cSwAJN 1942a. The parasites, predators, and inquiline associates of Antho­ phom li.nsleyi. American Midland Naturalist, 27(2) :402-417, 11 figs., 1 tbl. 1942b. Bionomics of the meloid genus Hornia (Coleoptera). Uni­ versity of California Publications in Entomology, 7 ( 9): 189- 206, pis. 6-7, 1 text fig. , 4 tbls. 1952. Notes on the biology and host relationships of some species of Nemognatha (Coleoptera: Meloidae). The Wasma.nn Journal of Biology, 10(1) :91-102, 2 pis., 1 tbl.

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