HOW TO KNOW THE IMMATURE INSECTS 



sponsible for these stunted conditions. The gall-insects and leaf min- 

 ers are readily located within the galls and the mined leaves. Many- 

 other insects can be found on malnutritive plants even though the in- 

 sect pests are feeding underground. 



Fig. 38. Q, Wool sower gall, Andricus seminator Harr.; b, Spring rose 

 gall, Rhodites bicolor Harr.; c, goldenrod ball gall, Eurosto 

 solidaginis Fitch; d, Dryophanta galls, Dryophanta lanata Gill; 

 e mine of Phyllocnistis populiiella Cham. 



HOW TO COLLECT IMMATURE INSECTS 



1. Sweeping. — There are usually numerous nymphs and larvae that 

 live or hide in grass, weeds, shrubs and trees. Sweep the net back 

 and forth on those plants in order to get those insects into the net. 

 This method of collecting can usually give large returns. The con- 

 tents of the net should be examined often and the specimens remov- 

 ed before they are damaged by this vigorous treatment. 



2. Trapping. — Many insects are attracted to food, certain chemicals, 

 or places of shelter. We can use cans or bottles sunk into the ground 

 and baited with molasses, fruits or meat. Not only the nymphs or 

 larvae can be trapped in this way, but the eggs may also be laid by 

 the adults. 



3. Digging. — Many subterranean insects can be collected by digging 

 in the earth. You will be surprised at the large numbers of insects a 

 square foot of soil may contain. 



4. Hand Picking. — This is the simplest method to collect insects. As 

 a matter of fact, we use it frequently. When we see the insects we can 

 simply pick them up in our hands. However, some insects have 

 nettled hairs or strong mouth parts which may hurt the hands, there- 

 fore, it is advisable to use a pair of tweezers or forceps on some species. 



5. Netting in Water. — For the aquatic insects, a water net can be 

 used for scraping the bottom or passing through vegetation in water. 

 Occasionally the aerial net is used in water, but it is quite poor 

 economy. 



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