COLLECTING AND PRESERVING INSECTS BANKS. 



91) 



Fig. 155.— One of the Pompilid wasps. Priocnemis. 



SPECIAL KINDS OF COLLECTING. 



It is of great interest to any observer to find out what occurs in a 

 certain place or under certain conditions. For example, the insects 

 that are associated with ants, that are to be reared from fungi, that 

 occur along the seashore or 

 in caves, or to be taken 

 from a certain kind of 

 flower. This group or eco- 

 logical collecting is of in- 

 creasing biological interest , 

 since it shows what insects 

 are associated with each 

 other, compete with each 

 other, and may influence 

 each other's life. Many 

 prominent biological ques- 

 tions are opened by this 

 collecting, such as isolation 

 of allied species. Some of 

 the principal lines of this kind of collecting arc noted below. All 

 specimens collected under like surroundings should bear a label 

 indicating the fact. 



Flowers. — It will soon be noted by any one observing insects that 



certain species prefer 

 certain flowers. This 

 is especially notice- 

 able among bees, but 

 many Diptera (fig. 

 156) also show such 

 preference. Other 

 insects prefer flowers 

 of a certain color. 

 By watching certain 

 flowers year after 

 year one will pick up 

 many rare forms that 

 would not have been 

 captured by desul- 

 tory collecting, and 

 at the same time gather many facts about habits and occurrence of 

 insects that are as yet far too little known to entomologists. For 

 taking insects from flowers one should not use a large or heavy net. 

 It is apt to break the blossoms so that they will attract but few insects 

 on following days, and a large net is apt to frighten away other insects 

 88552— Bull. G7— 09 8 



the Syrphid.k. Syrphus ribesi: a, Fly; 6. 

 I l.w \; v, LARVA; </. e, DETAILS. 



