56 THE AMERICAN MONTHLY [Feb., 



Collecting and Studying Parasitic Insects. 



By HERBERT OSBORN, 



AMES, IOWA. 



While the common insect parasites attecting birds and 

 mammals are usually looked upon as rather disgusting and 

 uninteresting creatures, they may become to the micros- 

 copist objects of no little interest. They possess num- 

 erous points of structure adapting them to a very pecu- 

 liar mode of life, some of which are remarkably interest- 

 ing but since they can only be observed with consider- 

 able magnification, they are of course unseen by any but 

 a microscopist. The collector need only to conquer a dis- 

 like caused by the habits of these animals to find in them 

 sources of interesting study. They may be collected 

 from both birds and mammals, the groups which are re- 

 ferred to here occurring only on warm-blooded animals. 

 For preservation, they may be put in vials of alcohol or 

 mounted in Canada balsam on slides and where speci- 

 mens are abundant, it is advisable to preserve some by 

 both of these methods. Fresh specimens may be mounted 

 in balsam and can be studied at once, but the balsam will 

 cloud later and remain so for perhaps some weeks, so that 

 if it is expected to study the specimens for some days 

 after mounting, it is better to first dehydrate them with 

 alcohol and clear with oil of cloves before using balsam. 



Alcoholic specimens may at any time be mounted in 

 balsam, clearing with oil of cloves, chloroform or othei- 

 clearing agent. Frequently specimens can be collected 

 from the skins of dried birds or mammals in museums, 

 and will frequently be found in excellent condition at 

 least for the study of the more important parts in iden- 

 tification. Such specimens will often exhibit air s])aces 

 which interfere with their study and injure the beauty of 

 the mounts, but I have found it quite an easy matter to 

 remove these air spaces by jiutting the specimens undej. 



