172 



INSTRUCTIONS FOR COLLECTING INSECTS. 



the aid of pincers. 



Fig. 9. Fig. §. rp|-^Q specimens should be placed at such a 



distance from each other that they may con- 

 veniently, and without risk, he removed and 

 replaced — an operation which is performed with 

 a steel pincers, having the shape indicated in 

 the figure, (fig. 8.) The handle should hs 

 large enough to allow a firm grasp of the hand, 

 and the h ranches should he kept constantly a 

 little separated by means of a spring, as repre- 

 sented. The jaws of the pincers should be 

 roughened like a file on the inside at the ends, 

 and they may be either straight, or, still better, 

 slightly curved, (fig. 9,) as in the figure, to 

 admit of being passed more readily beneath the 

 insect. 



The cases used on excursions, or entomologi- 

 cal trips, are difl'erently constructed from 

 those of the cabinet. The Ijottom must be lined 

 with a material soft enough to allow every pin, 

 even the finest, to be inserted easily without 

 The best material for this end is pasteboard, 

 which is cut in narrow strips glued against each other, so as to be in 

 a position perpendicular to the bottom of the box. 



^'s-'i-(>- The bottom of the box is lined with 



these strips, so that the pins move between 

 the layers of the pasteboard. To prevent 

 the pins so loosely inserted from dropping 

 out, the lining should be sufficiently thick, 

 and, at the same time, the box low enough 

 to allow the head of the loosening pin to 

 lean against the cover before dropping. 

 (See fig. 10.) 



Note by B. OstensacJcen. — Collectors of 

 Diptera should always endeavor to obtain 

 both sexes of every species. The sexes in 

 the families of the Tipulidae and of the 

 Asilidae (for the greater part) are easily 

 distinguished by the form of the abdomen, 

 which is generally club-shaped or obtuse 

 in the male, and more or less pointed in the female. In other fami- 

 lies {Tabani, Syrphi, StraHomijdae, Bomhjlii, and in most of the true 

 Muscidae) the eyes are close together in the male, and separated by 

 the "front" in the female. Sometimes they are separated in both 

 sexes, but then the front of the male is generally narrower than that 

 of the female. If these characters fail to help in distinguishing the 

 sexes, the size, and especially the shape, of the abdomen will be suffi- 

 cient. The males are, for the most part, smaller than the females, 

 and have the abdomen more slender. 



It often happens that one of the sexes appears in great abundance, 

 while not a single specimen of the other can be sean. In such cases 



