OCCASIONAL PAPERS OF THE MUSEUM OF ZOOLOGY UNIVERSITY OF MICHIGAN ANN ARBOR,MICHIGAN UNIVERSITYOF MICHIGANPRESS BIOLOGY AND METAMORPHOSIS OF SOME SOLOMON ISLANDS DIPTERA. PART I : MICROPEZIDAE AND NERIIDAE* DURINGthe recent war I served in the Solomon Islands with a United States Navy Malaria and Epidemic Control unit which was responsible for the control of arthropods of medical impor- tance. Since it is possibIe that some of the poorly known flies of that region are actual or potential vectors of epidemic dis- ease, knowledge of their general biology might be of prophy- lactic vaIue, and I therefore observed the habits and reared the larvae of many of the Diptera encountered. Regardless of possible epidemiological significance, the in- formation gained concerning the life cycles aid biology of the sixty-one species reared seems to be of sufficient interest to warrant publication. Restricted to a relatively unstudied region, many of the species collected were new, and nearly all of the larvae are undescribed. In several instances, the larvae and puparia collected are the only immature forms known i11 * Contribution from the Department of Zoology and from the Biologi- cal Station, University of Michigan. 1- was aided by an appointment to a Rackham Special Fellowship. -This article has been released for pub- lication by the Division of Publications of the Bureau of Medicine and Surgery of the United states' Navy. The statements and opinions set forth are mine and not necessarily those of the Navy Department. 2 Clifford 0. Berg Occ. Papers the genus, the subfamily, or even the family which they rep- resent. In the present paper, the first of a planned series, the occur- rence and general biology of Micropezidae and Neriidae found on Guadalcanal and New Georgia Islands are discussed, and immature stages of Mimegralla albimana, striatofasciata Ender- lein, Micropezidae, and Telostylinus l6neokc.tus (Wiedemann), Neriidae, are described and figured. To ensure accuracy of proportions, tracings of micro-projector images were utilized as the basis of all drawings. I am indebted to Mr. George C. Steyskal, of Detroit, Michi- gan, for identification of the Diptera, and to Dr. C. F. W. Muesebeck;of the Bureau of Entomology and Plant Quaran- tine, United States Department of Agriculture, for identifica- tion of the hymenopterons parasites. Miss Grace Eager, artist at the University of Michigan Museum of Zoology, and Mr. Joseph C. Bender, formerly an assistant in the Depart- ment of Zoology, University of Michigan, gave valuable assist- ance in the preparation of illustrations. Several recent papers on the Micropezidae and Neriidae (Enderlein, 1922 ; Frey, 1927 ; Czerny, 1930, 1932 ; Cresson, 1930,1938; and Hennig, 1934-35, 1935-36, 1937) present con- siderable information on the taxonomy and systematic rela- tionships especially of the Palearctic, Nearctic, and Neotropi- cal species. As already stated by Curran (1934: 306) and Cresson (1938: 296), very little is known about their early stages and habits. MICROPEZIDAE , Wheeler (1924) and Dorn (1928) reported on the habits of Micropezidae, and Hennig (1935-36 : 214-17) reviewed the fragmentary knowledge concerning the biology of the family. The only published descriptions of immature stages seem to be those of Fischer (1932), concerning " Crallomyk anfiulata (Fab.) ," and Sabrosky (1942), -dealing with the puparium of RairJieria brunneipes (Cresson). Published records of Micropezidae from the Solomon ~slandsappareiitly are con- fined to those of Mimegralla cmtingens salomonis Hennig, NO. 503 So1omo.n Islalzds Diptera. Part I 3 described from two specimens collected on Shortland Island (Hennig, 1935-36 : 192-93), and a "poorly preserved speci- men belonging to the genus Mimegralla" from Malaita Island (Curran, 1936 : 30). The five species of Micropezidae to be discussed here include four which were recently described from specimens collected on Guadalcanal (Steyskal, 1947) and one, Mimegralla albimuma striatofasciata Enderlein, which was collected on both Guadal- canal and New Georgia Islands, although previously reported only from the Bismarck Archipelago. The four species de- scribed by Steyskal are Eurybata tetras, Gongylocephala atra, Gorzgylocephala pdlicFe, and Grammicomyia bergi. Adult specimens of these five species and larvae and puparia of Mimegralla a. striatofasciata are deposited in the University of Michigan Museum of Zoology. Imagoes of Mimegralla a. striatofasciata are also deposited in the American Museum of Natural History and in the United States National Museum. Mimegralla a. striatofasciata is abundant in the jungle areas of Guadalcanal and New Georgia. Adults are often observed resting or running about on leaves of jungle underbrush with their wings folded compactly over their abdomens and with their long, narrow front legs waving before them like an- tennae. Hennig (1935-36 : 216-17) emphasized that this habit, characteristic of several species of Micropezidae, often contributes toward a remarkable mimicry of certain Ichneu- monidae. It is striking in this species because of the sharply contrasting white of the fore tarsi. They feed on excrement, carrion, and putrescent fruits. Copulation, which usually takes place on a large leaf, is similar to that reported for another species of this family by Wheeler (1924). Male and female remain together for ten to fifteen minutes, alternately standing still and walking about. The male fore tarsi are held parallel on the sides of the female prescutum while his other tarsi remain on the leaf. The habits of the four other micropezid species are not well known. All specimens were taken in moist, shaded situations ranging from open woodland to deep jungle. The copulatory 4 Clifford 0. Berg OCC. Papers behavior of Go~ngylocephalaatra is similar to that described above for Mimegralla a. striatofasciata. On three occasions immature stages of Mimegralla a. striato- fasciata were discovered and reared. Larvae occur in moist, decaying vegetable matter and probably eat this substance or the fungus which grows on it. In the laboratory they thrived in this material, which was kept moist and exposed to the air, and made no attempt to leave it before pupation. They move slowly and crawl about relatively little. The average duration of the pnpal stadium is thirteen days. On October 13, 1944, a single puparium was found beneath the moist bark of a fallen tree near the Tenaru River, about one and one-half miles from its nlouth on the north coast of Guadalcanal. The adult emerged six days later. On January 6, 1945, at least forty larvae were collected from beneath the wet bark of a large dead hardwood tree trunk lying on the bank of the Little Tenaru River, two and one-half miles from the north coast and one and one-half miles from the site of the October collection. Twelve larvae were im- mediately killed and preserved. By January 10, more than half of those remaining had pupated. The first five emer- genees occurred between 7: 30 and 8: 30 on the morning of January 19. Six more adults emerged between 6: 30 and 7 : 00 on the following morning, and nine between 7 : 00 A.M. and 8 : 00 A.M. on January 21. After six flies had emerged on the next two mornings, the few remaining pupae were pre- served. Although emergence had continued for five days, it was limited in any given day to a duration of one hour some- time between 6 : 30 A.M. and 8 : 30 A.M. This seems to indicate marked diurnal periodicity in the activity of the pupa. On February 22, 1945, larvae of Mimegralla, a. striatofas- ckta were found living in the pulp surrounding the seeds of , sago palm, Metrozylom sp., which were lying on moist ground near Yankee River, one-half mile from the north coast and four miles from the two earlier collections. Several larvae had pupated four days later. The only adult flies obtained from this collection were two which emerged on the morning of March 10. No. 503 Xolomo?z Islands Diptera. Part I 5 011 March 24 and again on March 28 some small parasitic Hymenoptera were found in the rearing jar. One of these was identified by Muesebeck as belonging to the Pteromalidae, probably an undescribed form in the genus Xpala~gia. The others he identified as Tricl~opria11. sp. (Diapriidae). Each I of the puparia parasitized by the latter species yielded several parasites. One puparium with two emergence holes (PI. 11, Fig. 3) still contained fourteen Trichopria pupae in a series of stages of development. Fischer (1932: 22) found a micro- pezid puparium parasitized by a species of Diapriidae, later described by Ogloblin (1934) as Trich&ria lamellifera. Ten preserved mature larvae of @!inzegralla a. striatofasciata (Pl. I, Fig. 1) range 8.2-11.1 mm. in length, average, 10.0 nnm.; nzaximam width, 1.3-1.8 mm., average, 1.6 mm. The larva is white or very light gray, nearly cylindrical, taper- ing anteriorly, and some~lhattruncate posteriorly. There are twelve visible segments : one small pseudocephalic, three tho- racic, and eight abdominal. The larva is amphipneustic, bearing anterior spiracles on the first thoracic segment and posterior spiracles on the eighth abdominal segment. Spinulose areas, used in locomotion, occupy the ventral an- terior part of each abdominal segment. These areas on ab- domiilal segments 1-7 (Pl. I, Fig. 2) are fairly uniform, each composed of a posterior'row of minute, crowded spinules with combined bases, ail intermediate row of larger, individual spinules, an irregular front row, and several scattered spinules anterior to it. Most of these spinules are simple conical proc- esses, quite blunt, and directed backward. The spinulose area - 011 the eighth abdominal segment differs from the others in that the posterior row is represented by only two small trifid sclerites. A few larger spinules are scattered irregularly around the anal plate. The anal plate (Pl. I, Fig. 2) surrounding the median, longi- tudinal slit is a chitinized region of blunt, irregular elevations immediately behind the spinulose area of the eighth abdominal 6 Cliford 0.