BibliograpMcal Notice. 323 



Dr. Thomas euters at great length into the question of the clas- 

 sification of the Orthoptera, and gives a complete revision of all the 

 more important systems which have been proposed by various 

 authors, from Linnajus downwards. His final result is an adoption 

 of Burmeister's classification of the families, except that he includes 

 the Forficulidai, placed by Burmeister as a distinct tribe. He 

 divides his Acrididse into two subfamilies, the Acridinaj and the 

 Tettiginse, and the former again into seven groups, as shown in the 

 foUowing Table (p. 40) :— 



I. Anterior margin of the prosternum truncate, not 



elevated ; claws furnished with pulvilli ; pro- 



notum shorter than the abdomen Subfam. 1. AcRWiyjB. 



A. Antennae G-8-jointed, not longer than the head Group 1. Frosc&pini. 

 AA. Antennae multiarticulate, longer than the 

 head. 

 a. Head produced in front in the form of a 

 cone or pyramid ; face very oblique ; an- 

 tenna; ensiform, triquetrous. 



b. Elytra narrow Group2. Tryxalini. 



bb. Elytra very broad GroupS. Trigonopterygini. 



aa. Face suboblique or vertical. 



b. Antennae filiform, subdepressed, or cla- 

 vate ; joints indistinct. 



e. Prosternum unarmed Group 4. (Edipodini. 



cc. Prosternum spined Group 5. Acridini. 



bb. Antennae acuminate; joints distinct; 

 front more or less advanced between 

 the antenniE, in the form of a blunt 

 cone. 



c. Joints of antennae flat Group 6. Xiphocerini. 



cc. Joints of antenna; terete Group 7. Phymatini. 



II. Anterior margin of the prosternimi elevated ; 



claws without pulvilli ; pronotum extending to 



the tip of the abdomen Subfam. 2. TETTiGiXiE. 



A. Prosternum unarmed Group 8. Tettigini. 



Mr. Walker's Pamphagidae are included in the group Xiphocerini. 

 Five of the above groups have representatives in the fauna of the 

 United States, the first, third, and seventh being deficient. In the 

 present work, however. Dr. Thomas works out the genera and species 

 only of four groups, the Tettiginse being described chiefly from the 

 writings of previous entomologists. 



The author tells us that the number of species of Acridida) (ex- 

 clusive of Tettigiuai) known to occur in the United States is about 

 120, belonging to 25 genera. The number described in Fischer's 

 'Orthoptera Europaja' (1853) was 77, belonging to 20 genera. 

 The total number of species (including 20 Tettigina)) found in the 

 North-American region (taking in British America, Mexico and 

 Central America, and the West Indies) is 227 ; these belong to 45 

 genera, 4 of which are Tettigine. Characters of these, principally 

 compiled from the Avritings of other authors, are given as a sort of 

 appendix to the body of the " Synopsis." Of the 120 species in- 

 habiting the United States, 40 have been described as new by the 

 author in this and former memoirs ; and he tells us that many of 

 these have been figured by Professor Townend Glover in a lately 



