Jan., 1908.] The Ohio Species of the Genus Disonycha. 429 



dead, it was probably that of D. quinquevittata. It was an 

 elliptical, capsule-like body,, about J/4-inch long with the outside 

 covered with fine grains of sand. The pupa stage probably lasts 

 from six to nine days as in xanthomelaena. 



Thus the development may be said to require from forty to 

 forty-five days. The reason for the adults and larvae overlap- 

 ping so much during the early part of the season may be attrib- 

 uted to the difference in the time of the appearance of the adults 

 in the spring. The whole life cycle is probably an adaptation to 

 the peculiar conditions of this locality and may very likely differ 

 much from the normal cvcle under ordinarv conditions. 



Fig. 3. Egg of Disonycha Fig. 4. Newly hatched larva of 



quinquevittata. Disonycha quinquevittata. 



Another species, Disonycha pensylvanica, variety pallipes 

 also occurs in this region, although not as abundant as the pre- 

 ceding form. The beetles are somewhat smaller than D. quin- 

 quevittata, not so oval and have sub-sulcate elytra and a parallel 

 form. The black elytral vittae are also much wider, giving the 

 insect a much darker general appearance. 



The eggs are laid in small bunches on the surfaces of semi- 

 erect leaves of Polygonum emersum. The young larvae at once 

 begin feeding upon these leaves, which soon become perforated 

 with small holes and turn brown. 



When the larvae are full grown the}^ crawl off this plant to 

 neighboring stalks of the Burr Reed — Sparganium eurycarpum. 

 Each larva bores into the thick lower part of a leaf or stalk of 

 this plant and forming a little cell for itself, lies head uppermost 

 and here pupates. The pupae are bright orange or salmon 

 color. Each stalk of the second host plant may contain a dozen 

 or more pupae lying end to end in separate cells. 



The length of the various stages of this species were not 

 determined, but it is probable that the life cycle occupies some- 

 where near the same period as D. quinquevittata, since both 

 occur so close together. 



The writer wishes to express his sincere thanks to those who 

 have, in various ways, contributed to the success of this work. 

 Among these, should be mentioned first. Professor Herbert 

 Osborn, under whom the work was conducted and whose val- 

 uable suggestions have aided in no small way the character of 



