Sept. 22, 18S2.] 



* KNOWLEDGE 



277 



(Flydrcecia micacea), the Bullrush {Nonagria typhce), and 

 he Silver Y {Plusia gamvia). 



Is^ow is the time to begin pupre digging, as a very large 

 proportion of our British insects have retired into the 

 pupal state for the winter, and a great part of them take 

 up their quarters under the eartL The operation consists 

 in digging round the roots of trees with a trowel, or a 

 small spade, preferably the latter, to the depth of about 

 six inches, and tlioroughly examining the earth as it is 

 turned up. The modus operandi is first to turn up a 

 spadeful, and after breaking it into small pieces with the 

 hands, and tearing all roots asunder, in case any pupie of 

 the BoMBYClD.E should be present, to carefully scrutinise 

 every inch of it, and if any chrysalides are found, to pick 

 them out, box, and bring them home. This requires more 

 practice than any other branch of insect collecting, as the 

 pupae are so very often of the same or a similar colour to 

 the earth by which they are surrounded, that a very 

 particular examination is necessary to find every chrysalis 

 contained in the earth just lifted up. 



The Reverend Joseph Greene, one of the most careful 

 and painstaking pupa-diggers ever known, says that 

 " parks and meadows with scattered timber trees " are the 

 most likely spots to yield a good harvest, whilst " those 

 trees from which the surrounding grass has been worn 

 away by the feet of cattle (in such a manner as to leave a 

 ring round the trunk, for if the cattle come too close they 

 do harm) and those situated on the borders or banks of 

 streams, dykes, Jcc, when the soU is dry and friable, will 

 be found most remunerative." 



The best trees are the oak, ash, beech, and elm, whilst 

 the poplar, willow, birch, and hawthorn, though not so 

 good, will often prove very productive. 



The following is a short list of the pupa; to be found at 

 the roots of the first-mentioned trees : — 



Oak. — Oak Beauty {Ainphijdasis prod ro mar ia). Great 

 Prominent {Xolodon/a trepida). Lunar Marbled Brown 

 (Noiodonta chacnia). Marbled Brown {Xotodonta dodonea), 



Ash. — December moth (Pcecilocampa popidi), Coronet 

 {Acromycta Ugiutri), ic. 



Beech. — Coxcomb Prominent {Noiodonta camdina), 

 Square Spot (Tephrosia consonaria), Nut-tree Tussock 

 (JDemas coryli). Red-necked Footman (Lii/iosia ruhricollis), 

 &c. 



ElM. — Lime Hawk moth (Smerinthus siUtf), Scarce 

 Umber {{Hyhernia auraukaria). Spring LTsher {Uybernia 

 leucc^hearia), March moth {Anisopleryx ascnlaria), Spraw- 

 ler ^I'etasia cassinen), "White Spotted Pinion (Cosmia 

 dijffinis), Grey Shoukkr-Knot {Xylina rhizolilha), &c. 



There are numerous other methods for obtaining pupa? 

 besides digging, and in next paper we will describe tiie 

 most generally employed, as space forbids this week. 



ARE TOADS POISONOUS? 



Sir, — In answer to this quer)-, propounded by Mr. 

 Herbert Brown in a recent No. of Knowledce, a decided 

 affirmative may be returned. The toad is venomous, though 

 not in the way that is implied by the general acceptation of 

 that term, as is commonly believed. Nothing can be more 

 harmless than thi; bite of the common toad — if it can be 

 said to bite, for it has no teeth. But the glands coi\tained 

 in the papilhv and rugosities of the skin covering the 

 back, and espeoially those which can be plainly seen 

 in the form of two bean-like eminences just behind 

 the head, secrete a milky, highly-acrid fluid, which is 

 exuded profusely on irritation. Indeed, if it were not 



for this poisonous secretion, the poor toad •would fall 

 an easy victim to many enemies, having neither 

 the agility of the frog or lizard to enable it to 

 make its escape, nor the teeth and claws of other rep- 

 tiles wherewith to defend itself. Cats, which are eager 

 hunters of frogs for food, spit and foam at the mouth when 

 they pick up the wrong batrachian by mistake, and are 

 often afi"ected in a similar manner to Mr. Brown's St. 

 Bernard ; frog-eating snakes, too, detect the diflference, and 

 will not take toads, as a rule. When a snake, greatly 

 pressed by hunger, swallows one, it usually rejects it again 

 immediately afterwards, and not unfrequently dies. Those 

 frogs which prey upon their own kind (as most frogs do) 

 despise their ugly relative from an alimentary point of 

 view ; and, curiously enough, certain toads which devour 

 frogs share the same antipathy to their race. Except 

 with very small animals, the poison appears to act 

 rather as a local irritant than a tox:emic agent ; 

 it has no eflect upon the sound skin, but will cause any 

 abraded surface to inflame to extensive ulceration, while 

 great pain results from its application to the conjunctiva 

 or internal mucous membranes. Any one who can over- 

 come his repugnance to the creature sufficiently to put his 

 lips or tongue against the skin of an angry toad will 

 experience an intensely acrid taste ; he should shut his 

 eyes in making such an experiment, as the post-occipital 

 glands sometimes emit their secretion in a jet. Mr. Frank 

 Buckland quotes a case which occurred in Oxfordshire, 

 where a drunken brute bit a toad's head off Happily, his 

 teeth went right through these glands, and his mouth and 

 throat immediately became swoUen and inflamed to such 

 an extent, that his life was in jeopardy for some hoiirs. ■ 

 These characteristics are much more strongly marked 

 in many of the tropical Bufonidu'. ily giant toads 

 {Bufo agua) used to swelter venom when they were 

 taken in the hands in such abundance that it would 

 pour off their backs and drip from them, before they 

 became tame ; and I was thus enabled to collect 

 a large amount. This species feeds on rats, and it 

 is possible that this copious exudation may serve to pre- 

 vent their prey from biting them when seized by the leg, 

 or otherwise awkwardly caught. I once put a " cribo " 

 snake {Dromicus fugitivtis) into a box with three of these 

 toads for a single night, for lack of other accommodation ; 

 it was a fine active specimen, five or six feet long, and its 

 movements during the night so disturbed them, that in the 

 morning I found the floor of the box all awash with fluid. 

 The snake was lying on its back, apparently dead : and, 

 though it recovered somewhat on being plunged into a 

 bath, it survived only a few days. 



Arthur Str^vdlixg, C.M.Z.S. 



CuRiocs Way of Utilizixg A.\ts. — Some interesting facts arc 

 coiitribnted to a scientific journal in a little paper sent by Dr. C. J. 

 Alacgowan from Han Chow, Province of Hainan, China, on the 

 " Ctilization of Ants as Insect Destroyers in China." It seems that 

 in many parts of the province of Canton the oraugo trees are ia- 

 jurod by certain worms, and to rid themselves fi-om these pests, tke 

 iuluibitants import ants from the neighbouring hills. The hill 

 people throughout the summer and winter find the nests of two 

 Bpciios of ants, red and yellow, suspended from the branches of 

 various trees. The " orange ant breeders " are provided with pig 

 <ir iroat bladders baited inside with lard. The orifices of these they 

 ap|ily to the entrance of the bag-like nests, when the ants enter the 

 blailiKrs, and, as Dr. Macgnwan expresses it," become a marketable 

 commodity at the orangeries." The trees are coloniieU by placing 

 the ants on their upper branches, and bamboo rods are stretched 

 between the different trees, so as to give the ants easy access to the 

 whole orchard. This remedy has been in constant use at least since 

 10 10, and probably dates from a much earlier periotl.— Fra ii fc 

 Leslie's ." 



