INTERDEPENDENCE OF ORGANISMS 47 



The Insect 



Order to which it belongs. 



Family. 



Solitary or gregarious. 



Stage found. 



Parasites or hyper-parasites. 



Inquilines. 



Summarize the results of the preceding study in a table 

 of the orders of the gall makers, prepared with the following 

 column headings. 



Order (of insects, or mites) 



Mouth parts (biting or sucking) 



Habits (solitary or gregarious). 



Gall type. 



Then state any relation appearing i) between type of 

 mouthparts and type of gall, and 2) between order of insect 

 and type of gall. 



III. THE RELATIONS BETWEEN ANTS AND APHIDS. 



Aphids are familiar plant pests which infest our fields and 

 gardens. They are minute Hemiptera, possessed of a slen- 

 der proboscis, with which they puncture soft plant tissues 

 and suck out the sap. Some aphids, which attack develop- 

 ing plant tissues, will already have been found in the 

 cavities of the galls to which they give rise. All are gre- 

 garious in habits, mainly because their great reproductive 

 capacity is coupled with poor power of locomotion. Genera- 

 tion after generation they are wingless : but when the time 

 for their wide dispersal is at hand, a winged generation 

 appears, which flies freely in search of new locations. 

 Autumn is the time of dispersal of most species, because of 

 the general failure of food supply at that time, and the 

 necessity of relocation for winter: but the failure or un- 

 favorable alteration of food supply may occasion the pro- 

 duction of a winged generation at any time. 



