CURRENT NOTES. 137 



notes are conspicuous by their complete absence. One genus only has 

 an analysis of the species allied to the new one attached to it to show 

 its relational position. It seems worse than useless to publish these 

 isolated and unconnected descriptions, which can be used only when 

 access can be had to a large mass of material. (2) "Field notes on 

 Virginia Orthoptera," by Henry Pox, is full of biological notes which 

 should prove of value. The summaries of the observations such as 

 Lists of species typical of different areas, the Appalachian Mountain 

 Province, the Coastal Plain, the Austral types in different provinces, 

 etc., and the detailed topography of the localities, are all very useful for 

 further work on the distribution of groups and species. 



The Annual Address to the Entomological Society of London dealt 

 with the subject of " Convergent Development among certain 

 Ectoparasites." The President^the Hon. N. C. Eothschild, was unable 

 to be present owing to ill-health and the address was read by the Eev. 

 Jas. Waterston. The following is a list of the families and groups of 

 insects in which ectoparasite species exist and which live on warm- 

 blooded vertebrates. 



a. With sucking mouth -parts. — Anojjlura, Cimicidae, Polyctenidae, 

 Siphonaptera, Hippoboscidae, Nycterihiidae,, and Streblidae. 



b. With biting mouth-parts. — Mallojyhaga, Heynirneridae, and 

 Platypsyllidae. 



Other insects may be called semi-parasitic, such as certain 

 Staphylinidae found on mammals in S. America and the blind Silphid 

 beetle, frequently observed in the burrows of mice. The admirable 

 statement of the nature and conditions of this parasitism may be 

 interestmg to our readers. " Parasitism is not an original form of 

 existence ; on the contrary it is an acquired habit, acquired slowly 

 through ages. Parasites are derived from non-parasitic forms, and 

 the alteration of habit is accompanied by corresponding morphological 

 changes. Parasitism and non-parasitism are two conditions somewhat 

 analagous to pathological and normal states, the pathological being a 

 modification of the normal or healthy tissue. The study of parasites 

 and parasitism is fascinating and delightful to the speculative mind, as 

 a comparison between the various parasitic insects and their non- 

 parasitic relatives enables the observer to trace changes and modifica- 

 tions, which are more appparent among parasites than among normal 

 insects. Ectoparasitism is a mode of life adopted by the members of 

 several orders of insects, either in one stage of the life of the individual, 

 or throughout its entire existence. In some cases it is only the young 

 stages which adopt an eetoparasitic existence, for example, many 

 mites ; in others it is the imago only which is an ectoparasite, for 

 example, fieas ; while in others again, the parasitic habit obtains from 

 birth to death, as in the case of Anoplura and Mallophaya. Some of 

 these Epizoa never leave the host on which they dwell and feed, while 

 others are temporary visitors only when they are in need of food. A 

 third association appears to occur in at least one case, the case of 

 Heinimeriis, a parasite on an African rat, which appears to use its host 

 more as a means of locomotion than for any other purpose, it being 

 supposed that the Hetnimerus does not secure any food from the skin of 

 its host. The gi'eat variation which obtains in the degree of parasitism, 

 in the numbei- of hosts frequented, and in the orders from which 

 parasites are derived, has naturally produced numerous and varied 



