ANTS. 



off their preserve. Still the above observations show that notwith- 

 standing the protecting guard of ants, the aphids require a special 

 \\rupon, which may annoy, though it cannot kill, their enemy. 



" Kven more- -inking i> the use of the tubercles in the case of the 

 lady-bird heetlo ( L'occinellidie ), those well-known enemies of the aphids. 



On the approach of one of these 

 beetles, the rose-aphis at first 

 seeks safety in her long legs, 

 which, when touched, apprise her 

 of danger before the enemy can 

 reach her body. Sometimes she 

 merely turns to one side without 

 drawing her proboscis out of the 

 plant tissues, at other times she 

 lets herself drop bodily to the 

 ground. If change of place does 

 not put her out of reach of dan- 

 ger she begins operations with 

 her tubules and smears the whole 

 forepart of the beetle with their 

 secretion. Usually the volley 

 does not fall so much on the 

 beetle's face as on its prothorax 

 under which the head may be so 

 far withdrawn as to suggest that 

 this retractility may be merely 

 a means of protection in just 

 such emergencies." 



Mordwilko has shown that 

 the siphons are best developed in 

 certain species of Aphididae that 

 live singly and not in droves or 

 colonies and are not attended by 

 ants, whereas these repugnatorial 



glands may be vestigial or completely lacking in the species habitually 

 thus attended. This is certainly suggestive of their great importance as 

 organs of defense. Many aphids, too, secrete a thick covering of white 

 wax, which may protect their thin-skinned bodies from the attacks of 

 some of their enemies. In this connection, Mordwilko has called atten- 

 tion to the long, projecting anal spine of certain aphids. This he inter- 

 prets as a mean of defense against the ants themselves, since it must 

 hinder them in directly imbibing the drops of honey-dew. In the same 



\ 



FIG. 208. Carton tent like the one 

 shown in Fig. 207, but opened to show the 

 coccids and the walls of the edifice. (Orig- 

 inal.) 



