OF WASHINGTON. 411 



soil which its victims frequent. It departs somewhat frcm the 

 normal habits of the family, and exhibits to us a sort of cuckoo 

 parasitism, differing from our ordinary conceptions of parasitism 

 in that, by mimicry and deception, it outwits the mason-bees, by 

 securing for its own larva the food which these more venomous 

 creatures have stung and provisioned for their young. The vic 

 tims of Miltogramma are wasps of the genera Ammophila, Oxy- 

 belus, etc. This last genus, for instance, digs chambers in sand 

 and provisions them with other insects which it paralyzes and 

 prepares for its young. The female Miltogramma lurks in the 

 neighborhood of the burrow or follows the wasp therein, and 

 places an egg or a young larva on the food thus stored by the bee. 



Gyrnnosoma is another i; teresting genus of the family, which, 

 according to v. Heyden, lives as larva in the abdomen of certain 

 Heteroptera (Pentatomids) ; while the Ocypterida? (considered 

 a su -family of the Tachinids by Osten Sacken) have been reared 

 in similar fashion from Pentatoma grisea, and from Cassida in 

 Coleoptera. The Phasiinas affect also Pentatomids, and even 

 Curculionida?, in Coleoptera. 



While the great majority of the Diptera, which are parasitic 

 upon other insects, belong to the family Tachinidaa, there are a 

 few others which have similar habits, as, for instance, the little 

 gray flies of the genus Leucopis, which are parasitic upon Coc- 

 cids and Aphidids. The Bombyliidas or bee flies must also be 

 included among the partially parasitic species, corresponding to 

 the Meloidae, in the Coleoptera. in their tendency to affect the 

 nests of bees and wasps and the egg-masses of locusts. The par 

 asitism here, as in the Meloids, is confined entirely to the larva, 

 which departs considerably from the typical Dipterous larva in 

 the more complete development of the head and mouth- 

 parts. Some of the Bombyliids are parasitic in the larvae of 

 Lepidoptera. especially those of certain Noctuidae, but these are not 

 destroyed until they have attained the pupa state. Little is 

 known of the early larval stages of the bee-flies, and it is not at all 

 unlikely that they will prove to be peculiarly modified and much 

 more active than in the later stages. This possibility is indicated 

 by well-known facts in reference to another interesting case of 

 Dipterous parasitism, viz., in the genus Hirmoneura, in the fam 

 ily Nemestrinidas. The eggs in this case are laid in clusters in 



