OF WASHINGTON. 403 



oviposit therein, and where the larva nourishes by absorption 

 of the surrounding fluids ; (b] external, or those which 

 merely fasten to the victim and suck its juices. This would in 

 clude species which may have in the female sex extremely well- 

 developed ovipositors, as in the case of Thalessa, but which are 

 more intended to penetrate the trunks of trees in order to reach 

 the burrows of wood-boring insects than to penetrate the bodies 

 of the larvae themselves. It may be still further subdivided into 

 those with a similar first larva, where the parasitic egg is fas 

 tened to or laid near the host larva, as in the case of Ophion and 

 Thalessa and many other Ichneumonids and Braconids and the 

 partially parasitic bees ; and those with a dissimilar first larva* 

 where the egg is laid away from the victim and the first larva 

 differs essentially from the later stages, as in some of the Diptera 

 and Coleoptera. This last category is again subdivisible into 

 the independent, or those which, as young larvae, have to seek 

 and make their own way to the victim ; and the dependent, or 

 those which, by means of special facilities, cling to the female 

 parent of the victim and depend on her to carry them to their 

 final prey. 



Third. Inquilinous Parasites. In this category should be 

 included all those guest-insects which sponge on the labors of 

 other insects, and these, again, are divisible into those which do so 

 at the expense of the host and those which live more or less 

 amicably or indifferently in association with the host, without in 

 jury thereto. The former might be denominated/a/al inquilines, 

 and the latter commensals. In the former we have to deal 

 with insects of at least four orders, and in the latter with the 

 Cynipidce inquilince, which take advantage of the galls produced 

 by the true gall-flies, and with the many interesting myrme- 

 cophilous and termitophilous species which have been so well con 

 sidered in papers presented to the Society by Mr. Schwarz. An 

 illustration of commensalism will also be found in the Coleopter 

 ous genus Antherophagus, which is always found in bumble-bee 

 nests and nowhere else. 



THE PARASITES AMONG INSECTS. 



In dealing with the subject of parasitism among Hexapods it 

 will prove convenient to do so by orders. 



