HOST RELATIONS OF COMPSILURA CONCINNATA 23 



GEOMETRIDAE 



Phigalia titea Cram, was very abundant for several years but is 

 now scarcely to be found. It has a variety of food plants, chiefly 

 oak, elm, and chestnut. It appears in the field early in June and 

 hibernates as a pupa. It is not a satisfactory host for Compsilura. 



Hydria undulata L. is a somewhat common, gregarious species, the 

 larvae of which web together the leaves of wild black cherry. Al- 

 though a great number of collections have been received at the 

 laboratory, it was not until 1922 that Compsilura was recovered. 

 The recovery of 2 adults from 6 larvae in one case and 11 adults from 

 200 in another would ordinarily be considered a fair host record, 

 were it not for the fact that all the past collections have resulted in 

 failure. In all probability this host was abundant at a time when 

 there was a shortage of favored ones. 



Ennomos subsignarius Hiibn. is a gregarious species and was 

 found in great abundance for three or four years, less abundantly 

 the fifth, difficult to find the sixth, and entirely absent the seventh 

 and eighth years. Larvae appear in the field early in May, com- 

 plete their larval stages in June, and issue as adults in July. The 

 species feeds on red maple principally and hibernates in the egg 

 stage. It has never been a much favored host. 



Cingilia catenaria Dru. has been received in abundance only dur- 

 ing the last four years. It appears in the field during late June 

 and has a great variety of food plants, including false indigo, birch, 

 huckleberry, and cherry. The species hibernates in the egg stage. 

 It has given a considerable number of Compsilura and has a better 

 host value than any other of the geometrids. 



Lycia cognataria Guen. and an unidentified geometrid are solitary 

 and are never found in abundance; the former feeds on willow and 

 hibernates as a pupa. As host insects their value is small. 



LYMNADIDAE 



Anosia plexippus L. was received in abundance in 1918 and in 

 smaller numbers the two preceding years. During 1919 to 1921, 

 inclusive, there were no collections received. In 1922, the insect was 

 found in small numbers and the 14 collections received represent only 

 a few individuals. The species is still scarce. Without exception, 

 its food plant is given as milkweed. The species is migratory and 

 winters as an adult in the Southwest. Three native parasites are 

 recorded from it and one of these, Frontina archippivora Will., is 

 of prime importance. The two remaining species (Winthemia ob- 

 scura Coq. and \_Exorista\ Zenillia vulgaris Fall.) are apparently of 

 little consequence. Frontina appears to meet but little opposition 

 from Compsilura and the sum total of its parasitism is much greater. 

 Over 50 per cent of the collections have given Frontina, whereas 

 Compsilura was recovered from only 11 collections. Superparasi- 

 tism is common with both species but particularly with Frontina, 

 where the average from one collection of 22 larvae was 4.86 per 

 individual. The best records found for Compsilura are thr:e adults 

 per individual. Multiple parasitism is uncommon, there being no 

 instance noted by the writers. In a general way, Anosia can be 

 considered a favorable host for Compsilura. 



