146 Psyche [Oct.-Der. 



the subject as a whole in its relation to animal ecology makes a 

 powerful appeal to the human imagination. 



It has been well understood that the presence of defensive or 

 repugnatorial scent glands in certain insects exists in direct adap- 

 tation to the needs and habits of their owners and in close response 

 to their environment; also that such glands are of very frequent 

 occurrence and with much variation as to position, form, and 

 function; and that their presence is of value to the insect for 

 repellent, defensive, and warning purposes. These eversible glands 

 most frequently occur in the form of simple hypodermic pouches 

 from which can be emitted, when desired, varying amounts of an 

 odorous spray capable of permeating throughout considerable sur- 

 rounding atmosphere. Biologically speaking, the principle involved 

 in such cases, though often modified, is practically identical with 

 that of the mephitic, sulphuretted, oil-like fluid ejected l)y the 

 skunks. Thus far anal glands are known to be present in the follow- 

 ing families of Coleoptera : Cicindelidfe, Carabidge, Dytiscidfe, Gyriu- 

 idse, Staphylinidfe, Silphidge, and Tenebrionidae. The blood itself 

 serves as a repellent fluid in the Meloidfe, and in the Coccinellidfe 

 and Lampyrida?, and it issues from a pore at the end of femur as 

 a yellowish fluid. The cantharidine in the blood of some species 

 of Meloidffi, commonly kno^\^l as "Spanish Fl}'," forms an espe- 

 cially caustic protection against birds, predaceous insects and rep- 

 tiles. A number of the Carabidse eject from a pair of anal glands 

 a pungent, acid, and often corrosive fluid, staining the hands a 

 rust-red color, and in Golerita janus Fab., the "Bombardier 

 beetles" (Brachums), and others, it "explodes" or volatilizes as 

 soon as it- comes in contact with the air, and the discharge and 

 jmff of vapor is accompanied l)y an audible report. This occurrence 

 may be repeated over and over again in succession at frequent 

 intervals. Westwood (1839) has recorded that specimens of a 

 Brachinits of large size from South America, when captured 

 "immediately began to play off their artillery, burning and staining 

 the flesh to such a degree that only a few specimens could be cap- 

 tured with the naked hand, leaving a mark which remained for 

 a cousidera1)le time." The odor of rose or hyacinth given out by 

 certain Cicindelida?, or the fragrance exhaled by the European 

 Aromia nwschata, are secretions probably formed by similar glands. 



