t48 ENTOMOLOGICAL NEWS. [May, '03 



minutes." Schwarz^^ has observed the ants pick up another 

 species of Hseterius and carry it to a place of safet}- in the 

 depths of the nest. These beetles are evidently fearless of the 

 ants, as they are well provided with the tufts of yellow glandu- 

 lar hairs characteristic of mymecophilous Coleoptera, besides 

 being almost invulnerable on account of their very hard bodies 

 and retractile legs. 



DIPTERA. 



SYRPHID^. 

 A most remarkable dipterous larva was collected in a nest 

 of Monomorium minutum Mayr., also at Pacific Grove during 

 April. So much does it resemble the slug-like larvae of the 

 Syrphid fly, Microdon, that I have no hesitancy in considering 

 it as a Syrphid larva. It is, however, so different in many 

 respects from the larvae of Microdon that it is, no doubt, a 

 member of some other allied genus. Larvae of Microdon oc- 

 curring in as widely separated localities as France, f the United 

 States, Mexico! and Paraguay, § are of an almost identical and 

 extremely peculiar type. The present form departs widely 

 from this, as can be seen from the following description and 

 appended figures. 



DESCRIPTION OF THE LARVA. Fig. 2, a, b, c.) 



Length 4.75 mm. — Broadly oval, much smaller and broadly convex 

 above, flat below. Ventral surface separated from the dorsal by a deli- 

 cate carina from which extends a delicate membrane. This membrane is 

 traversed by a series of fine thickenings (see Fig. i, a). At the anterior 

 extremity of the ventral surface is the mdistinctly tri-segmented oral pa- 

 pilla, behind which are irregular transverse rows of very small tubercles, 

 interrupted at the middle and at the sides. Just exterior to the membrane 

 is a single series of closely placed dart-shaped fleshy bristles, about 33 in 

 number. Above these are other similar bristles, four on each side and a 

 pair just each side of the anterior extremity. The sligmal protuberance 

 is placed well up upon the posterior surface of the body; conical and 

 sharply constricted at the base. Body elsewhere smooth but not shining. 

 Color in life lemon yellow ; after preservation in alcohol yellowish brown 

 above and fuscous below. 



Habitat. — Nest of Monomorium minutum Mayr. Pacific 



Grove, California. 



The occurrence of this enormous larva with such an extremely 



* Loc cit. 



t Poujade, Ann. Soc. Ent. France (6), iii, 1883, p. 23, pi. i. 



% Wheeler, Psyche, 1901. 



I Sharp, Cambridge Nat. Hist., Vol. vi, p. 502. 



