64 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



PREDACEOUS ENEMIES. 



Calosoma sayi Dej. — The larvte of the carabid beetle Calosoma 

 sayi were observed in considerable numbers and were reared to adults. 

 They were first noticed Jul}' (*>, when they Avere quite abundant in the 

 furrows between rows of sweet potato. They were found concealed 

 by the vines, feeding on the larva^ of the Prodenia, and after sucking 

 out the juices of one larva they immediately attacked another. The 

 adults issued in our rearing cages August 11. 



Polistes anmdaris L. — The large brown wasp PoUstes annularis' 

 was observed July 2, flying quite commonly in sweet-potato fields. 

 One was watched Avhich alighted on a leaf and began searching for 

 prey, after the custom of such wasps. The search was continued from 

 plant to plant and from leaf to leaf until a Prodenia larva was 

 located, when it was at once seized behind the head and chewed into a 

 shapeless mass. Other wasps of this species were also seen on fence 

 posts dragging Prodenia larva^ about with them. 



It is interesting to note that Mr. F. F. Crevecoeur, Onaga, Kans., 

 reports having seen this wasp being carried away by the asilid 

 robber-fly, Deromyia ternata Loew. 



Stiretrus anchor ago Fab., var. diana Fab. — The blue-and-red and 

 the uniformly blue forms of the soldier-bug Stiretrus anchoragOy 

 which are common in Florida, were observed in numbers attacking 

 the Prodenia larvae in July. 



Podisus maculiverdris Say. — During July the spined soldier-bug 

 was seen preying upon the Prodenia larva?. (See fig. 11.) In one 

 instance 18 nymphs were counted on a single amaranth plant infested 

 by the cutworm. The length of the life cycle of this sfjecies from 

 hatching (not from egg-laying) was determined to be 16 days in hot 

 July weather. 



Apateticus (Eupodisus) /nucronafus Uhl. — July 17, and again in 

 December, 190T, this pentatomid bug was observed preying on the 

 larva of this species of Prodenia at Orlando, Fla. It is considered a 

 rare species and this is probably the first observation which has been 

 made on its habits. 



Owing to the obscurity of the host insect in the past, no records 

 can be found of any of these parasites or of other natural enemies 

 which affect it, but in Smith and Abbot's work mention is made of a 

 species of " Ichneumon " which attacks the larva (see p. 58). 



Ponfia rapce L. — July 22, 1007, the young larvse of the imported 

 cabbage worm, which had hatched out on cabbage used as food for 

 Prodenia eridania Cram, in our rearing cages at Washington, were 



66— V 



