BIOLOGY OF SOME COMMON LAMPYRID.E. 49 



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measures about 8 mm. in this arcuate position, but when straight- 

 ened out it is about 10 mm. long. The lateral tergites project 

 slightly and each bears a group of short setae. The body is 

 somewhat flattened, being yellowish white in color except along 

 the lateral sides of the thorax and adbomen, which are slightly 

 pink. The larval light-organs function throughout the pupal 

 period and do not degenerate until shortly after the emergence 

 of the adult. The adult light-organs, which develope indepen- 

 dently of the larval organs, become functional shortly before 

 the adults emerge. 



Plwturus pennsylvanica DeGeer. 



This is one of the largest of our native fireflies throughout 

 central New York, and though very common in certain moist 

 localities, it is by no means our most common species. 



The adult insect is elongate, somewhat flattened, with the 

 head partially covered by the thorax. The head is rather 

 rounded, and slightly narrowed behind the large .convex eyes. 

 The antennae are eleven-segmented, slender and tapering, ex- 

 tending about half the length of the body. The prothorax is 

 rounded anteriorly and along the sides, and subtruncate pos- 

 teriorly. It is dull yellow with a central and basal dark stripe, 

 while the disc at each side of the dark area is red. The surface 

 is rather coarsely punctate. The elytra are elongate, extending 

 considerably beyond the end of the abdomen. They are brownish 

 except the lateral margins and a narrow tapering area extending 

 from the anterior part to beyond the center, which is a dull 

 yellow. The body is covered with short yellowish pile. The 

 length ranges from 12 to 15 mm. An illustration of the male is 

 shown on Fig. 3. 



The sexes are similar in form except that the female is slightly 

 larger than the male. The light-organs of the male cover the 

 entire sternites of the sixth and seventh abdominal segments 

 (Fig. 4), while these organs occupy only about two-thirds of 

 the corresponding region in the female (Fig. 5). In the male 

 the abdomen ends in a point while that of the female is truncate 

 on the tip. 



This insect is widely distributed throughout North America. 



