STATES OF INSECTS. 339 



Molorchus F. it is convex above in the former, and flat 

 in the latter, — the female of this beetle not unaptly repre- 

 senting some female Ichneumons in this respect, and the 

 male their males a . In Andrena it is oblong in the one, 

 and lanceolate in the other. In the hive-bee the drones 

 have a thick, obtuse, and rather long abdomen ; in the 

 females it is long, and nearly represents an inverted cone; 

 and in the workers a three-sided figure, or prism. 



The number of segments, also, is generally different in 

 the two sexes — the male having one more than the female; 

 but in Dytiscus marginalis, &c. the reverse of this takes 

 place : the female, if you reckon the bipartite half-con- 

 cealed anal segment as one, having seven ventral seg- 

 ments, and the male only six. She has also eight dorsal, 

 and the male seven. — In the ant tribes [Formica L.), the 

 little vertical scale, at the base of the abdomen in one 

 description of them, or the double knot in another, is 

 less in the male than in the female. In a very singular 

 male insect belonging to the Vespidce, and related to Sy- 

 nagris, (which I purchased from the late Mr. Drury's ca- 

 binet, ) the second ventral segment sends forth from its 

 disk two remarkable parallel very acute and rather long 

 spines. The same sex of Chclostoma maxillosa has like- 

 wise on the same segment a concave elevation, opposite 

 to which on the fifth is a cavity which receives it, when 

 the animal rolls itself up to take its repose b . In another 

 species, C. Campanularum, the segment in question has 

 only a tubercle c . 



On the second segment of the abdomen of some spe- 



a De Geer v. 151 — . 



b Mon. Ap. Angl. i. 177- 1. ix. Apis **. e. 2. y.f. 11. a, d. 



< Ibid.f. 13. a. 



z 2 



