112 H YMENOPTERA. 



wax-producing insects these glands are developed in great 

 numbers over certain portions of tbe body. In tlie Aphides, 

 whose bodies are covered witli a powder consisting of fine waxy 

 threads, these glands are collected in groups. Modifications of 

 them appear in the Coccid;ie. In the wax-producing Hymen- 

 op tera the apparatus is somewhat complicated. The bees 

 secrete wax in thin, transparent, membranous plates on the 

 under side of the abdominal segments. Polygonal areas arc 

 formed by the openings of an extraordinarily large number of 

 fine pore-canals, in which, surrounded by very numerous tra- 

 cheal branches, the cylindrical glan 1-cells are densely piled 

 upon each other. These form the wax organs, over Avhich a 

 fatty layer spreads. In those bees which do not produce wax, 

 the glands of the wax organs are slightly developed. AVax 

 organs also occur in the Humble bees. 



The honey is elaborated by an unknown chemical process, 

 from the food contained in the proventriculus, or crop, and 

 which is regurgitated into the hone^'-cells. 



The ovaries consist of many-chambered, four, six, or a hun- 

 dred, short tubes. "The receptacula seminis is nearly always 

 simple, round or ovoid, and necked, and is prolonged into a 

 usually short seminal duct." The glandula appendicularis con- 

 sists of a bifurcate tube which opens into the ductus seminalis, 

 and only rarel}' into the ccqjsida seminalis itself. 



In the Tenthredinidce , "this apparatus is formed on a 

 different type ; the seminal vesicle is a simple diverticulum of 

 the vagina, and more or less distinct from it, besides it is defi- 

 cient in the accessory gland. The copulatory pouch is absent in 

 all the Hymenoptera, as are also the sebaceous glands with those 

 females which have a sting and a poison gland," while in other 

 insects the sebaceous glands are present, and it Avould be nat- 

 urally inferred, therefore, that the two are homologous, but 

 modified for diverse functions. 



The two testes of the male are "composed of long follicles, 

 fasciculate and surrounded, together with a portion of the 

 torose deferent canal, by a common envelope ; but more com- 

 monly the two testes are contained in a capsule situated on the 

 median line of the body." (Sicbold.) 



The eggs are usually long, cylindrical, and slightly curved in 



