402 ENTOMOLOQICAL SOCIETY 



that insect parasites may, with propriety, be somewhat differently 

 arranged, and I would propose the following as a simple and 

 useful working system, which will include the great majority of 

 cases, but in the very nature of the case, not cover all the grada 

 tions : 



I. PARASITES PROPER. 



1. External. 



2. Internal, or sub-cutaneous. 



II. FATAL PARASITES 



3. Internal. 



4. External. 



A. Similar first larva. 



B. Dissimilar first larva. 



a. Independent. 



b. Dependent. 



III. INOJJILINOUS PARASITES. 



5. Fatal Inquilines. 



6. Commensals. 



First. Parasites Proper. Under this denomination I would 

 include all those insects which are born and go through their 

 whole life-development upon, and at the expense of, the host, and 

 which could not exist without it. It will include two subdivisions : 

 (a) external, embracing some of the Acarina, the Pediculina and 

 the Mallophaga, and (b} internal (or subcutaneous), such as the 

 various mites which produce mange or itch, or infest the passages 

 and muscular tissue, or even the quills in the case of birds. 



Second. Fatal Parasites. In this division I would include 

 the entomophagous parasites, i. e., those which live at the ex 

 pense of members of their own class, and, when once attached to 

 their victims, are sedentary or immovable. The parasitism here 

 is essentially larval, as, without exception, the parasitic life is con 

 fined to the larva state, and with few exceptions .it is the larva of 

 the host which is attacked and which, with equally few excep 

 tions, perishes from the attack. This, again, is further subdivis 

 ible into : (a) internal, in which would be included by far the 

 greater number of the Hymenopterous parasites, where the 

 female parent is provided with a peculiar ovipositor which 

 permits her to sting or penetrate the body of her victim, and 



