ART. 28 REVISION OF DISONYCHA NORTH OF MEXICO BLAKE 9 



The insect hibernates as an adult, and early in spring lays eggs 

 in groups on its food plant or the nearby soil. In Nova Scotia, 

 according to Whitehead, the eggs of latifrons, laid in April and 

 May, did not hatch till June, while in Washington, D.C., the eggs 

 of xanthoTnelas hatched in a week or 10 days, according to the tem- 

 perature. Likewise the larval stage of Jatifrons in Nova Scotia was 

 much longer, lasting from 50 to 55 days, and the pupal stage from 

 34 to 40 days. In the case of latifrons, the adult after emerging 

 fed " voraciously for a month or 6 weeks and then entered the 

 ground, vegetable matter, or rotten stumps where it hibernated." 

 In more southern latitudes, as at Washington, D.C., or in Kentucky, 

 the larval period is much shorter. In the case of xanthomeJas and 

 glabrata^ it was only 3 or 4 weeks, and the pupal period about 3 

 weeks. The larvae feed usually on the lower surface of the leaves, 

 often gregariously, at first eating holes and later stripping the leaves. 

 When full grown they enter the ground to pupate. The number of 

 generations of beetles probably varies also according to the length 

 of the season. 



MATERIAL EXAMINED 



I have been fortunate in having a large series of most of the 

 species to study at the United States National Museum, including 

 many of Schaeffer's types. Besides this, I hav? had access to the 

 LeConte, Blanchard, and Bowditch collections at Cambridge. I 

 wish to thank the following who have sent me material for study: 

 K. G. Blair, of the British Museum; E. T. Cresson, Jr., of the 

 Academy of Natural Sciences of Philadelphia; Dr. T. H. Frison, 

 of the Illinois State Natural History Survey; Prof. H. B. Hunger- 

 ford and Warwick Benedict, of the University of Kansas; Prof. E. 

 C. Van Dyke and E. P. Van Duzee, of the California Academy of 

 Sciences; Prof. W. E. Whiteiiead, of MacDonald College; and C. 

 A. Frost, Ralph Hopping, D. K. Duncan, H. E. Brisley, F. S. Carr, 

 and H. P. Loding. I am also indebted to Dr. W. G. Kuntzen, of the 

 Berlin Zoological Museum, and K. G. Blair, of tlie British Museum, 

 for comparing specimens with type collections, and to H. S. Barber 

 for his painstaking criticism. 



KEY TO THE SPECIES OF DISONYCHA 



1. Elytra iinicolorous, not vittate 2 



Elytra vittate, with dark margin H 



Elytra vittate or witli discoidal median spot, margin always pale 12 



2. Prothorax entirely dark funerea (p. 61). 



Prothorax yellowish, with or without spots or band, margin always pale_ 3 



3. Elytra yellow or yellow-brown 4 



Elytra blue, purple, or green 6 



175870—33 2 



