\\ \ |O\IY \\p i-n\ 



mity of tin- hair. Kulbnii, h ncnt hair- ... , m altO on the tl 

 Collcmbola, Aphidida- and other 



Nettling hair- or -pine- c lot he the < aterpillars of certain Saturniida 

 (Anlomcris), Li|>arida-, eh . Th< -i (Fig. 101), which arc sharp, 



brittle and tilled with poison, break to piece.- when the insect is handled 

 and Cause a cutaneous irritation nnich like that made by nettle I'-. 

 / crisf>til<i (\ : '\. IQJ) the irritating tluid i u.siial, by 



,d lar^e hypodcrmal cells at the base of each -pine. 'I heflC Irrit 

 hairs protect their possessors from almost, all birds except cuckoos. 



Repellent Glands. The various offen-i\< tlui.U emitted by insects 

 are also a highly effective means of defense against bird- and other in- 



orous vertebrates as well as against predacc- 

 ous in.-ects. The blood itself serves as a repellent 

 lluid in the oil-beetles (Meloidae) and Coccinellida-. 

 i- -u ing as a yellow fluid from a pore at the end of 

 the femur. The blood of Meloidas (one species of 

 which is still used medicinally under the name of 

 "Spanish Fly") contains cantharidine, an extremely 

 caustic substance, which is an almost perfect pro- 

 tection against birds, reptiles and predaceous insects. 

 Coccinellida3 and Lampyridae are similarly exempt from 

 attack. Larva,' of Cimbex when disturbed squirt 

 jets of a watery fluid from glands opening above the 

 spiracles. Many Carabidae eject a pungent and often 

 corrosive fluid from a pair of anal glands (Fig. After PACKARD. 

 148); this fluid in Brachinus, and occasional ly 

 in Galcrita j a tins and a few other carabids, volatilizes explosively 

 upon contact with the air. When one of these "bombardier-beetles" 

 is molested it discharges a puff of vapor, accompanied by a distinct 

 report, reminding one of a miniature cannon, and this performance 

 may be repeated several times in rapid succession; the vapor is acid and 

 rive, staining the human skin a rust-red color. Individuals of a 

 large South American Brachinus when seized " immediately began to 

 play off their artillery, burning and staining the flesh to such a degree 

 that only a few specimens could be captured with the naked hand, 

 leaving a mark which remained for a considerable time." (Westwood.) 

 \- malodorous insects, Hemiptera are notorious, though not a few 

 hemipterous odors are (apart from their associations) rather agreeable 

 to the human olfactory sense. Commonly the odor is due to a fluid 

 from a mesothoracic gland or glands, opening between the hind CO 



