252 JOURNAL OP ECONOMIC ENTOMOLOGY [Vol. 3 



Reviews 



A Monographic Revision of the Twisted Winged Insects Com- 

 prising the Order Strepsiptera Kirby, by W. Dwight Pierce, 

 Smith's Inst. U. S. Nat. Mus. Bull. 66, p. 1-232, 15 pis., 1909. 



In this importaut monograph Mr. Pierce has included practically all that 

 is known concerning the peculiar parasitic insects of the order Strepsiptera. 

 The work contains a detailed account of the systematic relationships of these 

 insects, of their relations to their hymenopterous and homopterous hosts, 

 their effects on these hosts, their taxonomy and geographical distribution, a 

 list of all the known species and a very complete bibliography. He thus, 

 presents us with an excellent foundation ou which all future students of the 

 group will have to build. To conservative entomologists it will seem that 

 Mr. Pierce has dealt with the taxonomy in a spirit of over- refinement, or 

 preciosity. Accepting Kirby's view that the Strepsiptera constitute an inde- 

 pendent order, he seems to feel that he must give this small compact group 

 of highly specialized parasites the status and dignity of one of the larger 

 orders. He therefore divides it into 4 superfamilies and 8 families. He cites 

 37 genera to include the 109 species; 25, or about two-thirds of the genera, 

 and 40, or somewhat more than one-third of the species being described as 

 new. The desire to fill out an order in this elaborately articulated manner 

 necessarily leads, in the case under discussion, to the use of rather meager 

 characters for superfamily, family, generic and specific distinction, and puts 

 the Strepsiptera out of all proper perspective to the other Insect orders. 

 Furthermore, the permanent value of these characters is rendered highly 

 problematical owing to the small amount of material examined, for the Strep- 

 siptera are by no means common in collections. Thus out of the 109 recorded 

 species, only 18 are known from specimens of both sexes, and 10 of these 

 belong to two allied genera. Of the 34 species enumerated in the largest 

 genus, Stylops, for example, specimens of 10 have not been examined by the 

 author, 15 are described from single specimens, 4 from two, 3 from three, 

 1 from four and 1 from five specimens. Some whole genera or even families 

 are based on only one of the sexes. Certainly the meager specific characters 

 utilized by Pierce can have taxonomic value only if it can be shown that they 

 are subject to very little variation. This is impossible, however, with the 

 very limited amount of material now on hand. Whether, under the circum- 

 stances, it is better to multiply species and genei'a and run the risk of sac- 

 rificing many of them to a future synonymy, or to proceed very slowly and 

 conservatively, especially when dealing with such a specialized and parasitic 

 group, is a matter on which there may be some difference of opinion. It is 

 certain, however, that the latter method, though it may seem to be more 

 timorous, may have the advantage of not burdening the nomenclature with 

 superfluous names, nor necessitate extensive taxonomic tinkering and read- 

 justment in the future. One of Pierce's reasons for multiplying species is to 

 be found in his assumption that every species of Strepsipterou has its own 

 particular host species. But in Acroschismus, of which he has seen more 

 material than of any other genus, this rule breaks down, for Polistes rubigi- 

 nosus is attacked by 4, and P. iexanus by two species of the parasites, and 

 one of these species is common to hoth of the wasps. If we accept this postu- 



