DESCRIPTION OF PLATE E. 



end in capacious tubes, with corrugated walls. These 

 taper as they pass downwards ; and their delicate ends 

 apparently terminate in the free fluids of the abdo- 

 minal region, and in spots largely charged with oil 

 globules: />, vulva; c c, fasciculi of muscles attached 

 to the vagina ; e e, colleterial glands and their ducts ; 

 d, spermatheca ; //, nectaries or cornicles; y, part of 

 the alimentary canal, which here takes the form of a 

 loop before its final descent to the tail ; h, Cauda. 

 112 diam. 



Fig. 2. — Nearly similar parts from another specimen 

 of Gallvpterus quercus ; but drawn in situ and without 

 compression, o, a large ovum, which has entered the 

 upper part of the dilatable vagina v, on its passage 

 towards b, the vulva. The liquid from the muci- 

 parous or colleterial glands would seem to affect the 

 egg shortly before its expulsion. Probably these 

 organs (c c) secrete part of the tough constituents of 

 the dark shell, which hardens after exposure to the 

 air. 52 diam. 



Fig. 3. — Portion of a same insect under the com- 

 pressorium. The colleterial glands {<• <■) are flattened 

 so as to show their transparent muscular walls. On 

 continuing the pressure on the specimen used, a short 

 membranous ovipositor was protruded, which was 

 found capable of retraction within the body- cavity by 

 the action of two bundles of muscular fibres seen at 

 //. At the same time a stream of spermatozoa (s) 

 diffused itself through the weak aqueous glycerine 

 which bathed this specimen. The abdomen contained 

 ten eggs in a forward stage of development. In 

 another example I counted thirteen. In the Aphidian 

 genera low in the scale, only one egg is produced by 

 the perfect female. 53 diam. 



Fig. 4. — Magnified view of one of the colleterial 

 glands. Its cavity contains folds of an excretory 

 membrane, from the walls of which the pouch is ailed, 

 as al ;/ and w; /■, excretory passage. 



Fig. 5. — Pari of the muscular coal of the last viscus, 



