140 CEREAL AND FORAGE INSECTS. 



laid by the middle of the preceding month, while in 1909 no pods 

 large enough to contain eggs were found in the vicinity of Clemson 

 College until September 7, when eggs and a few very small larvae were 

 found. Oviposition continues until the supply of green pods fails. 

 About a month after the first eggs are laid adults of the new generation 

 begin to appear. Repeated attempts were made to induce these young 

 beetles to oviposit, but entirely without success. In confinement they 

 fed readily on green pods, but would not oviposit when beetles of the 

 over-wintering generation were producing eggs freely under the same 

 conditions. It seems to be true that only one generation is produced 

 annually, but in localities where two distinct crops of cowpeas can be 

 matured there may prove to be two generations of the beetles. As 

 the season draws toward its close, individuals of the older generation 

 die off very rapidly. Probably few of them enter and none emerge 

 from hibernation the second winter. Of 11 beetles of the 1909 gen- 

 eration confined with food in a cage, 3 had died when the experiment 

 was discontinued late in the fall of 1909, while of 21 beetles of the 

 1908 generation confined under the same conditions, only 3 remained 

 alive at the same time. 



PARASITES. 



On September 18, 1908, there emerged from the sand in a breeding 

 jar a fly subsequently determined by Mr. D. W. Coquillett, of this 

 Bureau, as MyiopJiasia xnea Wied. (fig. 69). Between that date and 

 October 2, 1908, when the last one emerged, 60 of these flies appeared. 

 There were 683 beetle larvae put into these jars; 517, or 76 per cent 

 of the lot, emerged as adult beetles; 60, or 8.8 per cent, appeared as 

 parasites, leaving 15.5 per cent unaccounted for, but probably killed 

 by fungus or dryness. The flies belonging to this species emerged 

 during a period of from 16 to 28 days after the coleopterous larvae 

 entered the ground, the average for the lot being slightly less than 

 21 days. 



An examination of the puparium shows that the dipterous larva 

 does not leave the body of its host, but uses it for a pupal case. The 

 body swells slightly, becomes brownish and hard, and apparently no 

 attempt is made to pupate, the coleopterous larva dying soon after 

 entering the ground. The fly emerges through a transverse slit in the 

 posterior end of the puparium and seems to have no trouble in forcing 

 its way through any ordinary amount of soil to the surface. 



Numbers of the adult flies were confined in a jar containing a supply 

 of the beetles and green cowpea pods, in which eggs of the latter had 

 been laid. The actions of the flies were suspicious. They wandered 

 slowly over the pods, seemed interested in the punctures, and in several 

 instances were seen to touch the tip of the abdomen quickly to a 

 puncture. A careful dissection of the pods revealed nothing, how- 

 ever, that could be taken for eggs or larvae of the fly. In this connec- 



