16 American Midland Naturalist Monograph No. 3 



Some workers stain terminalia in order to make some of the delicate 

 structures show up more clearly. Staining is seldom necessary, so the tech- 

 niques have been omitted here. Good accounts of staining techniques are 

 given by Edwards (56) and Komp (100). 



Preparing Cibarial Armature for Study 



The cibarial ("pharyngeal") armature has been most extensively used 

 in separating subgenera and certain Old World species of Anopheles. Mich- 

 ener (122) discusses its use in separating mosquitoes of the Culex (Mela- 

 noconion) group in the southern United States. The methods for mounting 

 male terminalia are also applicable to mounting the cibarial armature. Since 

 these structures are so small, the chloral gum method will no doubt be pre- 

 ferred because of the fewer steps required. Specimens may be prepared for 

 study in the following manner: Heat the head of a female mosquito in a 

 10 to 20 per cent solution of potassium hydroxide for a short time; then 

 rinse in a small beaker of water for a few minutes. Transfer the specimen to 

 a drop of water on a slide under a dissecting microscope and break away 

 the head capsule with fine needles. The pharynx and cibarium are attached 

 to the hypopharynx, which may be transferred to a drop of chloral gum 

 mounting medium for further dissection. Application of a small cover slip 

 completes the mount. 



Dissection for Malaria Parasites 



Specimens containing blood should be kept either in test tubes plugged 

 with damp cotton or in humid lamp chimneys for about 48 hours, thus 

 allowing time for digestion. If a large number of specimens are to be dis- 

 sected, considerable time may be saved by anaesthetizing several at once and 

 placing them in a moist chamber. Care should be exercised not to prepare 

 more than can be examined in a half hour. If only a few specimens are to 

 be dissected, they may be transferred one at a time to a test tube and killed 

 by striking the distal end of the tube smartly against the palm of the hand. 

 It is not always necessary to remove wings and legs, especially where speed is 

 of primary consideration. 



Several techniques of dissecting mosquitoes for malarial oocysts and sporo- 

 zoites have been described by various workers, including Barber and Rice 

 (10), Blacklock and Wilson (20), Boyd (22), Christophers et al. (41), 

 Puri (139), Simmons and Aitken (173), and Wilcox and Logan (187). 

 The following technique has proven satisfactory for dissecting and preparing 

 the salivary glands and mid-gut for examination. Certain internal organs of 

 a female mosquito are shown in Fig. 5. 



Mid-gut. — Orient the body under a dissecting microscope on a slide con- 

 taining a drop of physiological saline with the abdomen pointing toward 

 the observer and touching the drop of saline. Nick the integument on both 

 sides of the penultimate abdominal segment, being careful not to sever the 

 hind-gut. With a needle held in the left hand, press down or transfix the 

 thorax in the region of the hind legs. Take the second needle in the right 



