and Laboratory Methods. 1129 



Easy Method of Mounting and Preserving Mosquitos. 



The present impetus given to malarial investigation requires the collection 

 and identification of these insects, and it is of importance that scientists and 

 physicians in this country should collect and identify such specimens as they 

 can obtain in their immediate vicinity, and more especially if malarial fever is 

 known to be present and proved microscopically. The calling of any and all dis- 

 eases malarial, or coupling them to typhoid or pneumonia, is to be discouraged, 

 and all physicians should have a positive blood test before treating or calling a 

 case such. 



Papers concerning this work will be found in British Medical Journal No. 

 2054, May 12, 1900, pp. 1183-1188; No. 2060, June 23, 1900; and in Prof. 

 Adann's Report on Tropical and Subtropical Diseases of Canada, p. 1544. 



A pamphlet on " How to Collect Mosquitos " has been issued by the Mon- 

 treal Natural History Society, and edited I believe from the British Museum. The 

 insects must be carefully pinned out or preserved, or they are injured in shipping. 

 The method used by Dr. D. C. Rees, in the London Tropical School, is as follows : 



(1) Kill in ordinary killing bottle, or chloroform, or tobacco. 



(2) When dead turn specimen on its back, separate legs, place large drop of 

 thick xylol balsam on slide, invert this gently on to the mosquito so as to pick it 

 up and not injure. 



(3) With fine needle spread and arrange wings and legs, and if necessary 

 press thorax down gently. 



(4) Pour on thin xylol balsam and straighten the antennae and proboscis as 

 it runs out. 



(5) Set aside to harden ; chip of? excess. 



(6) Place a glass ring about yL to -^ inch deep over specimen, and fill up 

 the chamber thus formed with balsam, the upper surface of which should be 

 convex, so that when cover is applied no air bubbles are included. 



(7) Let it harden, and then mail if desired. 



N. B." — ^If glass rings are not handy, balsam alone will do. (I use zinc 

 carpet rings.) If desired to photograph the insect, its parts must lie as nearly 

 in one plane as possible. This method is due to Dr. G. D. Freer, Colonial Sur- 

 geon, Penong Hospital. — B. M. /., p. 1468. 



Dr. John Reid, Redhill, Surrey, Eng., adds a note in regard to above. In 

 place of killing aphides, mosquitos, etc., coax them to get entangled in a drop of 

 glycerin, and with fine needles put in best position. Chemistry explains how 

 glycerol menstrum exhibits structure better than balsam, which refuses abso- 

 lutely to mix with aqueous media. Care and patience are required to prevent 

 injury and air bubbles. Glycerol jelly may be used if preferred, and the insects 

 die in more natural positions than in balsam. — B. M.J.., p. 1592. 



In reply to both, I prefer the carbolic acid method, or if desired carbolic and 

 glycerol, which I published some years ago. Glycerin is not always to be relied 

 on, especially if any chitinous or limy deposits are present. 



V. A. Latham, M. D. 



