HEMIPTEKA. 517 



The oesophagus is usjaally small and short, while the much 

 convoluted stomach is very long and subdivided, first into a 

 large, straight, glandular portion ; second, into the convoluted 

 smaller part, and third, in some Pentatomids and Coreidce 

 there is a third stomach "consisting of a very narrow, slightly 

 flexuous canal, on which are inserted two or four rows of 

 closely aggregated glandular tubes." (Siebold.) The Cicad- 

 idce, and most Heteropterous Hemiptera, have very large lobu- 

 lated salivary glands, divided into two unequal portions, and 

 often with long digitiform processes. 



In the aquatic species of the Naucoridce and Nepidce 

 there are only two stigmata at the end of the abdomen. In 

 Nepa and Ranatra the stigmata are situated at the base of a 

 long tube. There are four long urinary tubes. The ovaries 

 are formed of from four to eight tubes arranged in a verti- 

 cillate manner about the end of the short oviduct. In the 

 Psyllidce and Cicadidce, however, they are composed, in 

 the first family, of from ten to thirty unilocular tubes, and in 

 the second, of from twenty to seventy bilocular tubes. The 

 receptaculum seminis consists of one or two small caeca, and the 

 Cicadidce are the only Hemiptera which have a copulatory 

 pouch, this consisting of a pyriform vesicle. "The viviparous 

 Aphidce differ from those which are oviparous, in that their 

 eight ovarian tubes are multilocular and their oviducts entirely 

 without appendages, while with the second, or oviparous, these 

 eight tubes are unilocular, and there is a seminal receptacle 

 and two sebaceous glands." (Siebold.) The testes vary 

 greatly in number and form, consisting of from one to five 

 tubuliform or rounded glands. 



The active larvae of the Hemiptera, like those of the Orthop. 

 tera, resemble closely the imago, differing mainly in possessing 

 the rudiments of wings, which are acquired after the first 

 moulting. After two or more changes of skin they pass into 

 the pupa state, which differs mainly from that of the larva in 

 having larger wing-pads. While the development of the imago 

 ordinarily occupies the summer months, in the Aphides it 

 takes but a comparatively few days, but in the Seventeen-year 

 Locust as many years as its name indicates. An exception 

 to this mode of development is seen in the larva of the male 



