52 



Lattin: Introduction 



retaining and killing the specimens. Intro, figure 70 

 shows a common type, known as the New Jersey 

 light trap, which can be constructed with comparative 

 ease. It is desirable to have an electric outlet close 

 to the trap although battery operated traps can be set 

 up. A Coleman lantern on a white sheet makes an 

 efficient "light trap" and frequently is the best way 

 to collect many of the adult stages of aquatic insects. 

 Collecting at any light source near water usually 

 yields many adult aquatic insects, and neon lights 

 (especially blue) in towns are sometimes productive. 

 In general, insects fly to lights in greatest numbers 

 en warm sultry nights when there is little or no wind 

 and the moon is not too bright. 



Miscellaneous methods. — The aspirator (intro. fig. 

 71) is a device used to collect insects from the net, 

 from resting places under bridges and on vegetation, 

 and from microhabitats at the water's edge. The 

 insects are sucked into a tube and are later transferred 

 to a killing bottle. The insect fauna of sand or mud 

 may be collected by splashing water on the bank and 

 washing out individual specimens. The reverse can 

 likewise be done; that is, sand can be thrown into 

 the water to float off shore dwelling forms. This type 

 of collecting will produce larvae and adults of such 

 beetle families as Omophronidae, Staphylinidae, 

 Heteroceridae, and Carabidae and certain dipterous 

 larvae. Rocks in the intertidal zone of the seashore 

 are the special habitat of members of several families 

 of beetles (Eurystethidae, Staphylinidae). A crow bar 

 is useful to split such rocks and expose beetles that 

 have retreated deep into cracks. Some flying insects, 

 including large dragonflies, are practically inacces- 

 sible during the heat of the day but may be picked 

 from resting places on vegetation in the early morning. 

 Strong fliers which are otherwise unobtainable may 

 be "felled" at close range with fine dust shot from 

 a smooth-bore .22 caliber gun. A good collector does 

 not rely solely on specialized equipment but examines 

 every possible microhabitat — under stones, boards, 

 grass, and mats of vegetation or debris. 



AQUATIC COLLECTING 



The same intensive approach is necessary in aquatic 

 as in terrestrial collecting. Close attention should 

 be paid to the seemingly endless microhabitats includ- 

 ing surfaces of stones, aquatic vegetation, sunken 

 logs, and accumulations of debris. If trash and plant 

 materials are removed from the water and spread out 



Intro, fig. 72. Method of using insect net for stream 

 collecting (Ross, 1953). 



in the sun to dry, dozens or even hundreds of smal 

 insects will crawl out. Such trash may be raked froi 

 the bottom of a pond or stream, gathered in a net, c 

 collected from snags after a flash flood. Small Dryc 

 pids and other beetles may continue to emerge froi 

 drying trash for one-half hour or more. 



Nets and screens. — Water nets should be sturdif 

 than aerial nets. Nylon is desirable because of it 

 strength; also it dries quickly and hence can be use 

 for terrestrial collecting as well. The size mes 

 should be 24 to 32 strands per inch with mesh as ope 

 as is practicable to hold insects of the desired size 

 Mesh of too fine gauge drags the net and hinders th 

 capture of quick-moving insects. In streams, the n< 

 is held close to the -bottom, and stones and tras 

 are disturbed as the collector moves upstream (intrc 

 fig. 72). Insects are dislodged and carried downstrea: 

 into the net by the current. A piece of window scree 

 fastened to two strips of lath is particularly usefi 

 for this type of collecting (intro. fig. 73c). The scree 

 is stretched across a narrow section of stream, c 

 held with both hands, while the collector backs up 

 stream scuffing the bottom with his boots. In a ric 

 stream this method will yield enough specimens t 

 occupy the collector for a half hour or more, pickin 

 from the drying screen in direct sunlight. Small di 



Intro, fig. 71. Aspirator; a, two-hole rubber stopper; b, glass Intro, fig. 73. Specialized stream collecting e 



or copper tubing; c, fine copper screen; d, rubber tubing; e, glass ham scraper; b, Needham net; c. Lath screen 

 or plastic vial (Oman and Cushman, 1946). 1940). 



quipment: a, Nee 

 collector (Trave 



