BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [48] 



left. Tlie lawns in oiir parks and gardens are usually poor collecting ground on 

 account of the limited variety of plants in such, places ; biit the few species found 

 there occur in enormous number of specimens. The endless stretches of our western 

 j»rairies swarm at the right season (in June) with numerous Coleoptera (mostly Ma- 



-FiG. 67. — A Dermestid (Anthrenus scrophularice) . a, larva, dorsal view; b, larva, ventral view; c, 



pupa ; d, adult — all enlarged. 



lachiidse, Chrysomelidfe, Mordellidse, Curculionidse, etc.), provided prairie fires have 

 not swept too frequently over the place. Fires and cattle produce a remarkable 

 •change in the flora and fauna of the prairies; many indigenous species disappear or 

 become scarce and are replaced by a much smaller number of imported species. 



Sweeping may commence in the forenoon as soon as the dew has disappeared ; it is 

 less profitable in the heat of the midday, but produces the best results late in the 

 afternoon and more especially in the short interval from just before sunset until 

 ■dark. At this time many rare Pselaphida? and Scydmsenidse, species of the genera 

 Colon and Anisotoma, and other small Silphidae can be beaten from the tips of grasses, 

 all being species which can not, or only accidentally, be found during daytime, when 

 they hide between the roots of plants. 



Collecting on mud and gravel Banks. — The mud or gravel banks of rivers, creeks, and 

 stagnant bodies of water are inhabited, especially early in summer, with an astonish- 

 ing multitude of Coleoptera. Countless specimens of smaller Carabidse {DyscMHus, 

 Clivina, Bemiidium, Tachys, etc.) and Staphylinidse {Tachyusa, Philonthus, ActoMus, 

 Stenus, Lathrohium, Trogophloeus and many other genera) will be seen actively run- 

 ning over the mud or sand; many other specimens are hiding under the pebbles in 

 company with other species (Crypiohypnus, Georyssus, etc.) or in little subterranean 

 galleries {DyscMrius, Bledius, Heterocerus) . All these beetles must be collected by 

 picking them up with the fingers, an operation which, owing to the activity of the 

 specimens, requires some little practice. The beginner will at first crush or other- 

 wise injure many of the delicate specimens, the capture of which is moreover by no 

 means facilitated by the rapidity with which most of them are able to take wing. 

 The collector must necessarily kneel down and he must not mind getting covered 

 with mud. A good device for driving these species out of their galleries or from 

 their hiding places under stones or in cracks of the ground is to pour water over the 

 banks, and this can in most cases be done with the hand. Larger stones and 

 pieces of wood or bark lying on the bank are favorite hiding places of certain larger 

 CarabidfB {Nehria, Chlwnms, Platynus, etc.), and should of course be turned over. 

 Finally, the moss growing on rocks and logs close to the water's edge, and in which, 

 besides other beetles, some rare Staphylinidfe and the Byrrhid genus Limniclms can be 

 found, should be scraped off and investigated on the collecting cloth or on the sur- 

 .face of a flat rock, if such be conveniently at hand. 



