94 MAINE AGRICULTURAL EXPERIMENT STATION. I9O3. 



rounded bodies just posterior to the cerebral hemispheres. The 

 ventral nerve chain consists of a ganglionic mass separated into 

 two parts by a narrow constriction. The anterior mass is small 

 and closely united with the brain, the circum-cesophageal com- 

 missures being very broad and the aperture through which the 

 oesophagus passes far back. The second ventral ganglion is 

 large and lies entirely within the mesothorax. It gives off the 

 nerves to all the legs, and smaller branches to the organs of 

 the thorax. Structurally it is for the most part made up of nerve 

 cells, the amount of fibres being comparatively small. From the 

 posterior end of the second ventral ganglion a large nerve cord 

 passes posteriorly to the abdomen, giving off nerves to 

 the organs in each of the segments through which it passes. It 

 breaks up into a number of fibres in the seventh abdominal seg- 

 ment, the resulting fibres supplying the two posterior segments 

 of the abdomen. 



Reproductive System. The reproductive system of the female 

 insect (Fig. 51) consists of two ovaries, each made up of five 

 chambered ovarian tubes. The ovaries are large, extending 

 from the eighth abdominal segment to the anterior part of the 

 abdomen, filling the greater part of the abdominal cavity. The 

 vagina occupies the posterior part of the seventh and the whole 

 of the eighth abdominal segments. The seminal receptacle is 

 situated on the ventral side of the vagina in the eighth segment. 

 The oviduct opens to the exterior at the posterior end of the 

 abdomen between the valves of the ovipositor. The ovipositor, 

 is short, made up of two valves which are deeply concave on the 

 inner side. 



The male reproductive organs (Fig. 50) consist of the testes, 

 two rounded bodies situated dorsally in the fifth abdominal seg- 

 ment, one on either side. Coming from the testes the vasa defer- 

 entia make a complete turn and are then enlarged to form the 

 seminal vesicles. The two vasa deferentia unite in the seventh 

 segment to form a single tube which extends to the end of the 

 abdomen. At the point where the two vasa deferentia are united 

 they are joined by the ducts from the two large accessory glands. 

 The external genitals of the male consists of the penis and a pair 

 of well developed claspers. 



Respiratory System. The respiratory system of the adult 

 insect corresponds in arrangement very closely to that of the 



