56 THE A31ERICAN 3I0NTHLY [Feb., 



Collecting and Studying Parasitic Insects. 



By HERBliRT OvSBORN, 



AMES, IOWA. 



While tiie coniinon insect parasites affecting- birds aii(l 

 mammals are usually looked upon as rather disgusting and 

 uninteresting creatures, they may become to the micros- 

 (•o})ist objects of no little interest. They possess num- 

 erous points of structure adapting them to a very })ecu- 

 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 whicli 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 tliem witii 

 alcohol and clear with oil of cloves before using balsam. 



Alcoholic specimens may at any time be mounted in 

 Ijalsam, clearing with oil of cloves, chloroform or otlier 

 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 al 

 least for the study of the more impoi'tant parts in iden- 

 tification. Such specimens will often exhibit air spaces 

 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 putting the specimens tindci. 



