THE CANADIAN ENTOMOLOGIST 89 



NOTE ON AN INTERESTING CASE OF TWO GENERA- 

 TIONS OF A PARASITE REARED FROM THE 

 SAME INDIVIDUAL HOST. 



BY P. H. TIMBERLAKE, U. S. DEIT. AGRICULTURE, BUREAU OF ENTO- 

 MOLOGY, CEREAL AND FORAGE INSECT IN\ ESTlGATiONS. 



In. the course of inYestigations of Dinocampus americaniis 

 (Riley), a common Braconid parasite of many of the larger species 

 of Coccinellids, conducted in relation to cereal and forage crop 

 insects, several interesting features have developed, not the least 

 important of which is the discovery that parasitism is not invari- 

 ably fatal to the beetles. 



On September 5th, 1914, a beetle of Hippodamia convergens 

 in one of the writer's experiments was found giving issue to a 

 parasite which in due course of time spun its cocoon beneath the 

 host. The beetle, a large vigorous female behaved in the usual 

 manner of parasitized specimens, clinging tenaciously to the 

 cocoon and remaining in a comaltose condition for several days. 

 On the seventeenth of the same month it was found wandering 

 about the vial rather feebly, but of its own vol\j:ion, as if in search 

 of food. ha\-ing recovered to a large extent from its lethargy. The 

 beetle consequently Was fed with aphids and was seen to eat freely. 

 Within a few days it largely recovered its strength, seemed to be 

 perfectly healthy and ate freely whenever fed. On the eighth of 

 October, however, it was found in a weak condition and died 

 shortly afterward, having fallen a victim apparently to a common 

 disease of Coccinellids, which in its manifestations is somewhat 

 similar to the wilt disease of caterpillars. The beetle subsequently 

 was subjected to a thorough examination and dissection. The 

 wound on the dorsal side of the abdomen at the apex through 

 which the parasite had escaped was found completely healed over 

 by the deposition of black, chitinous matter. The ovaries were 

 developed considerably more than they could have been when the 

 parasite issued, although far from producing eggs, and in the ab- 

 dominal cavity the molt skin of the first stage larva was found. 



In the meantime out of a few beetles of the same species 

 collected on September 22nd and 23rd at Salt Lake City, Utah, one 



March, 1910 



