PAPERS ON ZOOLOGY 147 



THE COMPARATIVE MORPHOLOGY OF SOME 

 CARABID LARVAE 



C. C. HAMILTON, UNIVERSITY OF ILLINOIS 



Carabid larvae have been studied but little in America, and 

 it is generally believed that they do not possess distinguishing 

 characters. A morphological study, however, shows distinct 

 structural differences. These differences are found in the 

 comparative length, size, and shape of the segments of corre- 

 sponding structures. The number and arrangement of the 

 setae upon the various appendages and sclerites of the body 

 show distinct differences among the different species of larvae. 

 The antennae, mandibles, maxillae and labium are well sup- 

 plied with distinctive characters. The front and clypeus also 

 shows considerable variation in its comparative length and 

 width, the nature of its cephalic margin, and the number and 

 arrangement of the setae. 



SOME ADAPTATIONS FOR RESPIRATION IN 

 AQUATIC HEMIPTERA 



ABSTRACT 

 ANNA GRACE NEWELL, UNIVERSITY OF ILLINOIS 



In Benacus griseus, the "giant water bug," or the "electric 

 light bug," there is a pair of "strap-like appendages" project- 

 ing from under the wings, at the posterior end of the abdomen, 

 in both male and female. Their morphology and function 

 have not been exactly stated. 



On soaking specimens in caustic potash, these appendages 

 are found to be projections from and parts of the tergites of 

 the 8th segment. Similar organs are present in Belostoma 

 fluminea say (Zaitha), and very short ones in Notonecta. 

 Both are the same, morphologically, as the ones in Benacus. 



There is a large spiracle at the base not only of each pro- 

 jection, but also of a groove extending from the spiracle to 

 the tip of the "strap-like" portion of the tergite. This groove 

 is edged on both sides with a row of long, closely-set setae. 

 Records of observations* as to methods of breathing in Zaitha 



*Bueno, J. R. de la Torre: Life Histories of North American Water Bugs. 



I. Life History of Belostoma fluminea Say. Can. Ent. 1906; v. 37, 1906, 

 pp. 189-197 



II. Life History of Ranatra quadridentata Stal. Can. Ent. v. 38, 1906, pp. 

 242-252. 



