5S DR. LEIDY ON THE HISTOEY AND ANATOMY OF 



Abdomen of six segments, superiorly pubescent, inferiorly smootli, excepting along the course of the 

 spiracula, where there is a line of pubescence as far back as the last segment ; margins compressed ; 

 posterior three segments alated ; ala and dorsal plate of the last segment divided for the reception of the 

 caudal setffi. Caudal setae long, linear, viUose beneath, capable of being entirely retracted within the 

 abdomen. 



Imperfect Stages. The larva and pupa are both active ; they only differ from each other in size, and in 

 the absence of the rudimentary wings in the former. They are very flat superiorly, and nearly smooth, 

 Avith the exception of the under part of the abdomen which is pubescent. The antennae are not 

 completely formed. The tarsi have but a single joint, which by future development, is divided into the 

 two articulations of tlie imago, and there are two ungues to each foot. 



SPECIES. 



Belostojia grande. 



Nepa grandis. N. fusca flavo maculato. Fah. Ent. Syst. T. 4, p. 61 ; Sys. Hhyng. 



p. 106. Punaisesde Stoll. PI. 7, Fig. 6. Linn. Syst. Nat. T. 1. Lam. An. 



sans Vert. 2me Ed. T. 4, p. 164. 

 Belostomum grande. Burm. Handb. der Entom. 2er B. p. 195. 

 Belostoma Indica. Guerin et Percheron. Gen. des Insectes, Hemip. PI. 3. 



I have before me, while writing, three specimens of this species, one from Bengal 

 and a second from Surinam, belonging to the collection of the Academy, and a third 

 from China, for which I am indebted to Prof. Haldeman, as well as for several other 

 species. By careful comparison, I find them to agree with the descriptions of the 

 above synonyma. They measure from three inches, to three inches two lines in 

 length, and one inch two lines in breadth at' the widest part. Colour, testaceous with 

 dark brown maculae ; three of these, well defined, are upon the thighs and tibiae, and 

 a large one upon each side of the scutellum of the male, and a single larger one in 

 the centre of that of the female. The anterior thighs are very robust, one-third more 

 so in the female than in the male, and have on their anterior aspect, a double groove 

 with an intermediate ridge, corresponding to a single groove with raised edges on the 

 inner side of the tibise, which in a state of rest receives the latter, like the handle of 

 a penknife does its blade. The patch of fine pubescence of the hemielytra, is situated 

 about two lines from the membranoas portion, and is four lines long. 



In none of these specimens do the caudal setse project beyond the extremity of the 

 abdomen, although they may be withdrawn their full length, which is one inch. 



This species is found in the warmer parts of Asia and America. A smaller form 

 is found rather commonly in the lakes, ponds, and other still waters of North 

 America, variously considered as a variety and species. After careful comparison, I 

 think it but a variety of the former. It is well known under the name of B. 

 americana. A number of specimens in my possession, vary in their measurement 

 from one inch nine lines, to two inches three lines in length, and from nine to eleven 



