— 40— 



orifice in the terminal mandibular claw, which would occur here as well 

 as in all other Arachnida which have a poison gland in their mandibles. 

 But thev have another weapon, useful only for defense; for they can 

 emit a sharp and penetrating odor very much like acetic acid. The in- 

 habitants of some West India Islands therefore call them "Vinaigrier" or 

 vinegar maker. Where that odor gland is situated in the body of 

 T'lelyphoTius I am unable to say as my studies were confined only to 



dried specimens. 



EXPLANATION OF PLATE. 



Fig. I. Thdyphonus giganteus Latr. to show the mandibles and 



male {Thel. excubitor Girard). niaxillae. 



Fig. 2. Thdypltonus giganteus Latr. Fig. 6. Front from the side. 



female. Fig. 7. Abdomen of the male, showing 



Fig. 3. Sternal surface of the female. the sexual orifice. 



Fig. 4. Lateral eye eminence with the Fig. 8. Themandiblesseparated.a from 



five eyes. the inner side: b. from the outer 



P"ig. 5. Front showing the mandibles. : side. 



All the mouthparts are hidden ' tig- 9- On organ of special sense, situ- 



under a thick pubescence and 1 ated at the tibia of each leg. 



these hairs have been removed 



Remarks on North American Scolytids 



By E. a. Schwarz, Washington, D,C. 



Gnathotrichus matenarius. Dr. Packard in his Guide, p. 493, 

 (see also Bull. 7, U.S. Ent. Coram., p. 174) states that "a species, prob- 

 ably the Cryphalus mater iarius of Fitch" has been found to bore into 

 empty wine casks and spoil them for use. This is undoubtedly a con- 

 fusion of species, as G. niakriarius lives exclusively in pine trees.' The 

 species in question was probably Xyleborus fuscaius which, in my e.\- 

 perience, bores in several kinds of deciduous trees. 



Gnathotrichus asperulus is perhaps not rare; but not .easily 

 recoo'nized. It bears a close resemblance to the smaller and rubbed 

 specimens oi Pitvophthorus minutissimus, from which it differs mainly by 

 vestiture of the antennal club. I beat two specimens from Pinus imps 

 near Wa.shington in May. In this tree it will probably be found boring 

 in the same manner as G. materiarius. 



Pityophthorus. The first group of this genus (Leconte's group 

 B), at once recognizable by the fine and dense punctuation of the elytra, 

 includes a few easily distinguished species, mfesting deciduous trees. 

 The sexual differences seem to be alike in all species. The second group 

 (Leconte's group C), divides naturally into two sections: In the first the 

 elvtral declivitv is dissimilar in the two sexes. The three species which 



