86 Zoologica: N. Y. Zoological Society [HI; 3 



the petiole. Since the parasitized coccid remains in the food- 

 groove with its body in the usual position the cocoon necessar- 

 ily has the same position and orientation, i.e. \vith its long axis 

 parallel with the long axis of the petiole. The cocoon gradually 

 grows darker, passing from amber-yellow to dark brown and by 

 the time it has reached this stage, the dead tissues of the coccid 

 enveloping it, except those on the ventral side, between the cocoon 

 and the wall of the petiole, disappear, leaving the lateral and dor- 

 sal surfaces of the cocoon fully exposed. I am inclined to believe 

 that the dead tissues of the coccid are eaten away by the beetles 

 or their larvae, but as they are very soft and disintegrate easily, 

 they may perhaps be rubbed off merely by the attrition of the 

 insects as they move back and forth in the petiole. Two of the 

 denuded cocoons in the stage and with the orientation just des- 

 cribed are shown in Fig. 11. 



When the completed Blepyrus cocoon is cleared in carbol- 

 xylol, mounted in balsam and examined as a transparent object, 

 the larva is found to have pupated within it, after extruding a 

 number of large meconial pellets, the undigested remains of all 

 the food it swallowed while it was living on the tissues of its 

 host. In most cases, at least, the head of the pupa is at the caudal 

 end of the coccid. The imago, when mature, cuts a large round 

 hole in the end of the cocoon (see upper pai't of Fig. 11) and 

 emerges as a short, thickset, broad-headed fly, only 1.5 mm. long, 

 with a metallic green face, a black, more or less bronzed body, 

 black and yellow antennae and legs and basally infuscated wings. 

 It is very active, and like other small Encyrtids skips about by 

 using the long saltatory spurs on its middle tibiae. After mating 

 the female undoubtedly oviposits in the young coccids either in 

 the same or in some other beetle-inhabited petiole. 



This parasite seems not to be nearly so serious a menace to 

 the Coccidotrophus colonies as the Scymnus and Diadiplosis, since 

 the infested coccids are probably able to supply the beetles and 

 their larvae with honey-dew till both host and parasite are nearly 

 mature. Hence one often finds several infested coccids and 

 Blepyrus cocoons in petioles inhabited by flourishing beetle col- 

 onies. In one such colony I counted more than fifty cocoons and 

 a dozen large coccids swollen with parasites that were still in 

 the larval stage. 



