258 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



ventral side of the abdomen, and meets the pleurum on the side of the 

 body. 



In the female (Fig. 12, B), the abdomen tapers somewhat toward the end 

 of the body, to which are appended the two x^airs of stout, hooked spines, 

 forming the ovipositor (Fig. 12, Br,r^). The anus is situated above the 







Fig. 12.— External Anatomy of Caloptenus spretus : the head and thorax dis- 

 jointed. (Drawn by J. S. Kingsley.) 



upper and larger pair, and the external opening of the oviduct, which is 

 situated between the smaller and lower pair of spines, and is bounded 

 on the ventral side by a movable triangular acute flap, the egg-guide 

 (Fig. 1 2, B e, (7, and Fig. 14). Above the opening of the oviduct and between 

 the two pairs of spines forming the ovipositor is a sharp fork {\j\i^ furcxda 

 supra-vulvalis), which is really the third pair of blades of the ovipositor, 

 and well developed in the bee. At the time of egg-laying, the abdomen 

 may be lengthened nearly twice its usual proportions. 



