On some Drag"njl'es and their Prey. 405 



greatest width 730, distance of tips 390, breadth of pahn at 

 base 188. 



Named for Dr. R. Houy, Surgeon and Naturalist to the 

 German Boundary Expedition, whose untimely death by 

 the hand of his native servant we have to deplore. 



P.S. — When describing Biibahis caffer adaniau(E the 

 dimensions of the type skull were omitted by mistake. 

 They are given here : — 



Basal length 411 mm. ; palatal length 250; postorbital 

 width 20.5; mastoid width 213; nasals 177x63; horns, 

 length along outer curve .550, greatest width 525, distance 

 of tips 280, breadth of palm at base 155. 



LVIII. — Some Dragonfl'ies and their Prey. 

 By Herbert Campiox. 



It is a well-known fact tliat Odonafa, in all their stages, are 

 liigldy predaceous creature-!, and are veritable tyrants in the 

 insect-world. Prey is seized by the nymphs with the extra- 

 ordinary modification of the labium called the " mask." It 

 is customary for imagines, with which we shall deal exclu- 

 .«<ively on the present occasion, to take tiieir prey durino- 

 flight, and it may be assumed tiiat tliey capture the smaller 

 insects upon wliich they feed with the aid alone of tlieir 

 powerful jaws. Larger prey, no doubt, is caught and held 

 by the Dragonfly's spiny legs, the length and position of 

 which are such as to enable their possessor to bring all of 

 them simultaneously to the level of tiie mouth. 



The capacity for destruction possessed by Dragonflies is 

 enormous, and " Beutenmiiller found that one of the lar"-e 

 ones would eat forty house-flies inside of two hours, while a 

 smaller one ate twenty-five in the same time " (Dr. L. O. 

 Howard, ' Tiie Insect Book,' 1902, p. 3G5). On the other 

 hand, their power of resisting famine is consiJerable, and 

 during dull weather, when they fly very rarely, if at all, 

 they probably pass several days in succession without 

 obtaining any food whatever. In those countries, therefore, 

 where the sun shines without intermission for l^ng periods 

 at a time, the activity of Dragonflies must be much greater 

 than in cloudy climates, and the consumption of other insects 

 must increase in a corresponding degree. 



The principal source of our knowledge of what Dragonflies 



