BINUCLEATA 53 



dust. In their internal arrangements, these aquaria should reproduce 

 as nearly as possible the natural conditions under which the larvae 

 are found. 1 



Parasites in various stages of development are found in the mid- 

 gut and in the salivary glands of the mosquito. To examine these 

 the insect should be prepared as follows : 



Anaesthetize with ether vapour and, after removing the wings and 

 legs, place the insect upon a glass slide upon a dark background ; add 

 a drop of normal saline solution. With a sharp knife separate the 

 abdomen from the thorax in the 1st abdominal segment (fig. 11, 

 arrow A). Pins should be placed at the points in the figure marked 

 respectively a, b, c, and d, and, by careful pulling, the attachment 

 between the 6th and 7th abdominal rings should be released. The 1st 

 abdominal ring is held 

 firmly by means of a 

 pin through point e, 

 and, by carefully pulling 

 away the 7th segment by 

 means of the pin through 

 point c, the abdominal 

 viscera (intestines and 

 sexual apparatus) are 

 drawn out and may be 



directly examined in FlQ n ._D iagram illustrating the method of prepar- 

 the fresh state. The ing a mosquito for the microscope. (After Eysell, from 

 SO-called "cysts" of the Mense's Handb. d. Tropenkrankh.) 



malaria parasite will be 



seen in the wall of the mid-gut (fig. 12, w), and the Protozoa which 

 inhabit the lumen (the ookinets of the malaria parasite, intestinal 

 Flagellates) may be examined through the thin intestinal wall without 

 further preparation. Many of these, however, pass out with the bowel 

 contents when the gut is divided. 



To dissect out the salivary glands a preparation microscope should 

 be used. Press the neck forward by squeezing the thorax, and then 

 sever the anterior portion of the thorax by a cut in the direction 

 shown by the arrow B, fig. 11. With the assistance of two pins 

 inserted at / and g, the neck is split lengthwise as far as the 



1 Detailed instructions for rearing and keeping mosquitoes are given by Eysell, 

 "Die Stechmticken," Mense's Handb. d. Tropenkrankh., vol. ii, pp. 44-81 (Leipzig, 

 1905) ; by v. Wasielewski, " Studien u. Microphotogramme zur Kenntnis der patho- 

 genen Protozoen," part 2; " Untersuchungen tiber Blutschrnarotzer," 8vo, pp. 175 

 (Leipzig, 1908) ; by B. Blanchard, " Les Moustiques, Histoire naturelle et medicale," 

 8vo, pp. 673 (Paris, 1905) ; and others. 



