420 NATURAL HISTORY OF ARTHROPODS. 



erect. These young larvae issued in large numbers from the burrows in which they 

 were hatched, and, placing themselves in an upright position at the entrance, allowed 

 themselves to be blown away by the wind. Here for a time they have not been fol- 

 lowed, but it is probable tliat they attach themselves by the aid of their ventral hooks 

 to the bodies of large-sized beetles, the Bhizotrogus solstitialis, by which they are 

 carried into the ground when the female enters to deposit her eggs. This is probable 

 from the fact that hundreds of pupse and pupa skins were observed near the fence, 

 protruding from the ground^ and kept upright by means of their terminal booklets. 

 On searching below these, in every instance the remains of the larval skins were found 

 at the depth of about two inches, and still deeper, were found the remains of the above- 

 mentioned beetles, and in one instance the mature larvae were seen issuing from the 

 abdomen of the beetle. 



In the United States only three species of this family are known, a ERrmoneura 

 and two Bhynchocephali, the latter interesting froju the fact that the two other known 

 species of the genus, both very closely allied to ours, are inhabitants of the region about 

 the Black Sea only. 



The BoMBTmD.E will be recognized by their having the three basal cells much 

 prolonged, with usually four posterior cells, and the third joint of the antennae not 

 annulate. The family is a large one, comprising about fourteen hundred known species, 

 and exceedingly rich in varied forms, scattered over all parts of the world. They 

 are usually clothed with long and delicate hairs, and with the wings often with dark 

 markings. Most of them are very swift-flying insects, often hover- 

 ing motionless in the air for a time and then darting away with 

 the rajndity of the wind. They seek sunny places in woodland 

 roads, about blossoms, or on rank vegetation. Somhylius fratd- 

 lus ajjpears in Xew England often in March long before other 

 insects have become at all abundant. In general the members of 

 Fig. 5!n.—Jiombiiiius ^jjjg family are prettily marked, and in their life histories are often 

 . very interesting. In the adult state they are flower-flies, feeding 

 upon the pollen and honey which they extract by the aid of the proboscis, which is 

 often very long. 



JBombylms medms, an English species, lays its eggs near the entrance of the holes 

 of a large species of Andrena, whose larvae and pupffi are devoured by the fly. 

 Another species is parasitic upon Colias. B. major, a European species which also 

 occurs in the Pacific States, is also found in the subterranean nests of Andrena. 

 Other larvae of this family are parasitic upon species of Mec/ac7iile, Cemonus, Calico- 

 donia, Xiimacodes, Odynerus, Trypoxylon, etc. 



Among the most interesting, biologically, and at the same time exceedingly useful 

 insects are Triodites and Systcechus, a number of species of which occur from the 

 central to the Pacific States. Their larvse are found in the egg-pods of the locust 

 Caloptenus spretus, so destructive throughout the West. " These larvae begin to trans- 

 form themselves into the pupa state early in the summer, and the pupa pushes itseK 

 half way out of the ground in order to disclose the fly. These continue to issue during 

 the summer months. As a rule but one year is required for full development. 

 Triodites is first observed as a large, yellowish-white grub, about a half an inch long 

 when extended, it being usually curved so that the head and tail nearly meet. It is 

 usually found in a case of locust eggs which it has devoured, pushing the empty shells 

 aside, and at last occupying the space where were twenty-one to thirty-six eggs. Often 



