OF WASHINGTON. 407 



According to T. A. Chapman (Ent. Mo. Mag., vol. XXVII, 

 Jan., 1891, pp. 18-20) the eggs are laid in rotten wood in 

 autumn, and the " mite-like young larvaB " (triungulins) are car 

 ried the following spring by the female Vespa into her subterra 

 nean nests. The next step in the larval development is unknown, 

 except that the Metoscus larva is an internal feeder, living within 

 the Vespa larva, which, however, does not succumb until after it 

 has spun its cocoon, from which the perfect Metoecus issues. 



Myodites, another genus in which both sexes are fully developed, 

 has been observed to oviposit on flowers. The triungulin state 

 has not been observed, nor is it known whether the larva lives 

 externally or internally on its hosts, Augochlora and Nornada, 

 from the closed cells of which Myodites has been bred. 



Rhipidius (Symbius) is a curious genus parasitic upon the 

 common cockroach, Ectobia germanica. Here the female is 

 apterous and apodous, but with distinct head and provided with 

 eyes and n-jointed antennae, and with subobsolete mouth-parts. 

 The only form of the larva known resembles her in general shape 

 of body. The female is stationary within the body of the roach, 

 but otherwise very little is known of the life-history of the genus. 

 The parasitism in this species would come very close to my first 

 category, as the roach does not seem to be killed, but accom 

 plishes its transformations. It is probable that, when more is 

 known of the life-history of the Rhipiphoridae, hvper-rnetamorpho- 

 sis will be found to occur, and that in most characteristics they 

 truly connect the more perfect parasitic Stylopidaa with the next 

 family of Coleoptera to be considered in this connection, namely, 

 the Meloidae. The insects of this family, including the oil-beetles 

 and the blister-beetles, are, in their early states, partially parasitic 

 in the cells of bees and in the egg-masses of locusts. In the 

 genera Epicauta, Macrobasis, Henous, etc., the eggs are laid in 

 the ground, not necessarily near the locust eggs, though the female 

 beetle doubtless instinctively chooses soil which she knows to con 

 tain such eggs. The first larva or triungulin is active and seeks 

 the locust eggs. It possesses, as in all such cases, great vitality, 

 and can live a long time without food. 



In other genera, as in Meloe, Sitaris, Hornia, etc., the triungu 

 lins, after hatching, congregate on various kinds of flowers, and 

 are carried therefrom by the female of various species of mason- 



