418 NATURE SKETCHES IN TEMPERATE AMERICA 



At this time most of the individuals seen were pupse, but 

 associated with them were quite a number of adult males. 

 Some of the latter were wholly translucent white, having just 

 undergone the last moult. On removing a large-sized piece of 

 bark, under which these insects had congregated, it was remark- 

 able the swiftness with which they disappeared from sight. 

 Like a flash they all scampered into various accessible cracks 

 or crevices, hiding themselves wherever they could find cover. 

 The flattened bodies proved to be excellently adapted to slip 

 into narrow, confined places. A number of adult females were 

 also found, but these were alone on the ground as a rule, on 

 pieces of bark, seeming to indicate a desire on their part to 

 isolate themselves from the gregarious stump colonies nearby. 

 These insects are said to infest country houses, where they are 

 attracted by light. On account of their fondness for the paste 

 under the wall paper they cause much injury to these decorations. 



The young in various stages survive the winter on tree 

 stumps, and Blatchley mentions that "cold has seemingly 

 but little effect upon them, as they scramble away almost as 

 hurriedly when their protective shelter is removed on a day 

 in mid-January, with the mercury at zero, as they do in June 

 when it registers 100 degrees in the shade." 



The Pennsylvania cockroach is a moderately large species 

 of blattid; the male is shown in the left-hand figure of our 

 illustration. Its body is elongated and bears long membra- 

 neous wing-covers, or tegmina. The color of the insect is dark 

 brown, the centre of the pronotal disk being dark, while the 

 sides are translucent whitish during life. The female shown in 

 the middle figure of my illustration is .so remarkably different 

 from the male that for a long time it was taken for another 

 species by naturalists and described twice under different 

 names. An inunature individual was also first given a distinct 

 appellation until more definite observations of late have proved 

 that the young, the female and male thus described, all belonged 

 to a single species. The object shown to the right of the 

 illustration is the nymph's cuticle; it was moultetl from the 

 female some time before I took the photograph for the figure. 

 The insects forming the subjects of my three figures were found 

 at Flossmoor, Illinois, June 1, 1905. 



