370 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 83 



identifications are correct. Those specimens called P. plaiygaster, I 

 might say, judging from the description, may well be some other 

 species. The identification of P. hyalinus, on the other hand, is hkely 

 correct, although the possibihty of the specimens so identified being 

 carolinensis, a closely related but rarer species, which I have described 

 herein as new, must not be overlooked, for both species were considered 

 as hyalinus in the past. The types of Provancher's three species — 

 stygicus, aciculatus, and laevis — are in Canada; the first two are in the 

 Museum of Public Instruction in Quebec, and tlie last in the Harring- 

 ton Collection in Ottawa.^ I have not seen these, and I am unable to 

 place laevis, at least. P. aciculatus is probably hyalinus vSay, and I 

 have synonymized it, questioningiy, with tliis species. I am also 

 unable to place cyaneus Brulle, the type of which I presume to be in 

 the Museum d'Histoire Naturelle in Paris, or alexinus Walker, eniellus 

 Walker, and lepreos Walker, the types of which are presumably in the 

 British Museum. For a further mention of laevis, cyaneus, alexinus, 

 eniellus, and lepreos, see "Unidentified Species" (p. 410). 



Twenty-two valid species and varieties are recognized in this paper, 

 of which ten are described as new to science. 



As may be seen from the key or table to species, the genus Peri- 

 lampus divides itself naturally into two sections and each section in 

 turn into smaller groups of species.^ Section I, composed of what I 

 term the "carinate species", from the presence of a well-defined carina 

 on the frons, includes (1) the hyalinus group and (2) the plaiygaster 

 group ^; and section II, the "noncarinate species", includes (1) the 

 single species comprising the canadensis group, (2) the chrysopae 

 group, (3) the anomocerus group, and (4) the Julvicornis group. The 

 species canadensis, which stands at the head of the noncarinate list in 

 the key, could properly be included in the chrysopae group, but I prefer 

 to keep it separate, for the present at least, because of its resemblance 

 in certain respects, especially in the character of its fu'st tergite, to the 

 hyalinus group of species in section I. The following outline will 

 show the species in accordance with the above grouping: 



Section I (Carinate Species) 



I carolinensis, new species. 

 regalis, new species. 

 hyalinus Say. 

 'plaiygaster Say. 



2. Platygaster group. 



crawfordi, new species. 

 subcarinalus Crawford. 

 carinifrons Crawford. 

 vcellaius, new species. 



» Gahan, A. B., and Rohwer, S. A., Can. Ent., vol. 50, p. 100, 1918. 



« Only the principal characters are used in the key in dillcrentiating the groups, and in some cases again 

 the charactrrs uspd are not all true group characters. 

 ' The Rroup name is derived from the oldest described species in each. 



