208 ARTHROPODA 



small quantities it is apparently lapped up by the spoon and 

 transferred through the labium. 



A figure of the mouth parts is desirable. 1 



Sting. — The sting is to be regarded as a modified ovipositor 

 that is no longer concerned in depositing eggs, but has become 

 a weapon of offense and defense. It is accordingly present 

 only in the female. The queen never uses her sting except 

 on other queens. 



Remove the dorsal integument of the abdomen of either a 

 fresh or preserved specimen, and find the dark brown shaft 

 of the sting, near the posterior end. Grasp the shaft with a 

 pair of fine forceps and forcibly remove it. A considerable 

 mass of tissue will be removed adhering to the base of the 

 shaft, but this consists for the most part of accessory organs 

 that must be understood. Spread the sting upon a slide, and 

 either dehydrate and mount in balsam, or mount in glycerin. 

 The balsam mount will prove more satisfactory, but the cover 

 must be clamped down until the balsam hardens. 



1. The shaft consists of three parts: 



(a) A heavy support, called the awl or sheath, pointed at 

 its extremity and sending a pair of arms or arches from its 

 base, which normally bend ventrally, but are here forced to 

 the sides. At its extremity each of these arches enlarges to 

 form a rather large flattened plate, the sheath plate, to which 

 strong muscles are attached. 



(b) A pair of lancets which are fastened to the dorsal 

 surface of the sheath and the sheath arches by tongue and 

 groove joints (each tongue is enlarged along its inner margin 

 so that it is held firmly in the groove) . Each lancet is pointed 

 at its free extremity, and its sides near the point are set with 

 barbs that point toward the base of the sting. The arch of 

 each lancet is continued past the end of the corresponding 

 sheath arch, and is there articulated to one corner of a some- 

 what triangular plate. The remaining corners of each are 



1 The comparative study of the mouth parts of a butterfly, horse 

 fly, house fly, and mosquito will prove valuable. 



