February 1, 1894.] 



KNOWLEDGE. 



41 



endeavour to make clear what insects really are venomous, 



and what is the true nature of the stinging operation, as 

 well as to say a word on behalf of some that are commonly, 

 but calumniously, regarded as dangerous. 



Confining our attention to the fauna of our own islands, 

 we may state, in the first place, that the number of species 

 possessed of this power of annoyance bears an extremely 

 small proportion to the total insect population. The 

 power is not indiscriminately distributed, but is confined 

 to certain special groups ; so that if one can only acquire 

 a general knowledge of insect types and a readiness in the 

 art of classification, or recognizing at a glance the order 

 or sub-order to which an insect belongs, it becomes 

 a very easy matter to estimate on /( prinri grounds the 

 chances of its being a stinger. Whole orders, con- 

 taining thousands of species in our own country alone, 

 may be dismissed at once as including no members 

 that indulge in the objectionable practice. But before 

 indicating which they are, it will be necessary to define 

 somewhat carefully what is to be understood by the word 

 " sting." It is popularly used for at least four operations, 

 which difi'er more or less widely from one another. The 

 truest sense is doubtless that which implies (1) the making 

 of a puncture, for offensive or defensive purposes, by 

 means of a sharp-pointed and complex organ which is the 

 equivalent of what in other insects becomes an egg-laying 

 instrument, and is therefore placed at the hinder end of 

 the body, and (2) the injecting into the wound thus made 

 of some poisonous liquid secreted by the insect itself. The 

 injection of an irritant poison easily explains the intense 

 pain and other discomforts that follow such punctures. 

 But in some cases a puncture is made defensively by a 

 sharp-pointed instrument in the same position as above, 

 but no poison is injected, since the gland necessary for its 

 secretion is absent. Here no swelling or discomfort follows, 

 and the only pain that is felt is the sharp prick at the 

 moment when the puncture is made. By those who are 

 unfamiliar with the insects, this would be at first regarded 

 as a sting, for pain and inflammation are naturally expected 

 to follow a sharp puncture, and it is only when the efl'ect 

 is found to be transient that the difference between this 

 and the true sting can be discerned. 



The third kind is that in which a puncture is made by 

 a combination of fine perforating instruments which con- 

 stitute the mouth organs, and are therefore situated at the 

 head end of the body. In this case, as we have pointed 

 out on previous occasions, it is a moot point whether any 

 poison is instilled or not, no special poison glands being 

 discoverable, unless the saliva itself possesses an irritating 

 property ; but however that may be, the operation is 

 obviously one of a totally different character from those 

 before mentioned, and its purpose is not essentially 

 ofifensive or defensive, but consists merely of an endeavour 

 to obtain food, though on occasion, possibly, use may be 

 made of it for protective purposes as well. The two first 

 mentioned, as being purely strategic actions, so to speak, 

 are accomplished quickly by a sudden rapid plunge with a 

 hard and stiff weapon ; but the third is a slower process, 

 and usually consists in forcing a collection of exceedingly 

 thin and flexible hair-like organs gradually through the 

 skin. This also is often followed by painful swellings and 

 inflammation. All the actions already enumerated are 

 more or less under the control of the insects themselves. 

 But to these must be added those cases in which painful 

 swellings are caused by the mere handling of the insect, 

 through accidental contact with its glandular hairs, a 

 species of injury unintentional and entirely beyond the 

 control of its inilictor. 



Under one or other of the above four heads may be 



Fig. 1. — Antenna! 

 Hornot : A, male ; 

 tVm.ile. Magnified 

 diameters. 



arranged all the instances that may reasonably be described 

 as stinging, by whatever insect the injury may be inflicted. 

 Under the first head come the true vengeful stings, such 

 as those of bees, wasps, and ants ; under the third, the 

 punctures made by bugs, gnats, and other flies, in their 

 efforts to obtain the liquid food on which they subsist ; 

 flea-bites also may be ranked here, although there is some 

 modification in the shape of the organs concerned. Thus, 

 when we speak of the " sting " of a wasp, and the " sting " 

 of a mosquito, we are referring to two totally diS'erent 

 operations carried out by instruments placed at opposite 

 ends of the body, and for totally different purposes — the 

 one a fighting, and the other a 



/^ feeding action; the one for forcing 

 down poison into a wound, the 



g other for sucking up blood out of 

 a wound. Aristotle, and after him 



of PlLny, long ago pointed out this 



B, distinction, showing also that the 

 '^"'' tail-stingers, such as bees and 

 wasps, were /"ouc-winged, but the 

 iiitiutli - stingers, such as gnats and flies, tiro - winged. 

 Under the second head will be included any punctures 

 that may be made by ichneumon flies, which are the most 

 insignificant of all in their effects ; and under the fourth, 

 those painful swellings that are caused by the hairs of the 

 caterpillars of certain moths, such as the gold-tail and 

 brown-tail described in a recent paper, and the proces- 

 sionary moths of the Continent. This fourth group, again, 

 diSers from all the rest, in that the power of stinging is 

 possessed by the insect in its larval condition, whereas, 

 in all the other cases it pertains only to the adult. 



We are now in a position to consider, from the system- 

 atic point of view, what insects those are that possess the 

 stinging power in either of the senses described above. 

 All insects that can voluntarily inflict punctures, whether 

 distinctly poisonous or otherwise, with mouth or with 

 ovipositor, are included in three only out of the eight or 

 nine orders into which almost all insects are grouped, viz., 

 the Hymenoptera, to which bees, wasps, and ichneumon 

 flies belong ; the Diptera, containing gnats and other two- 

 winged flies ; and the Hemiptera, or bugs. Thus we may 

 dismiss from our thoughts altogether the following groups, 

 as having no share in the opprobrium that rests upon the 

 orders just mentioned: the order Coleoptera, containing over 

 three thousand British species, which consist of beetles of 

 all sorts, including many that have other popular names, 

 and are not usually called beetles, such as ladybirds, glow- 

 worms, weevils, cockchafers, and the like ; the Lepidoptera, 

 or butterflies and moths, with over two thousand British 

 species, if we except the two or three whose caterpillars have 

 irritating hairs ; the Neuroptera and Trichoptera, or dragon 

 flies, lacewing flies, and caddis flies, a total of between three 

 and four hundred; the Homoptera, or frog-hoppers and 

 plant lice, containing some hundreds of species ; and the 

 Orthoptera, or earwigs, cockroaches, crickets, and grass- 

 hoppers, a group feebly represented in this country, and 

 including only between forty and fifty species. Here, then, 

 we have a total of some six thousand British insects, 

 to none of which does the charge of stinging apply. But 

 this is by no means all, for of those three orders mentioned 

 above, which contain the stingers, the Hemiptera (excluding 

 the lice) yield only some half dozen, out of their total of 

 nearly four hundred and fifty British species, against which 

 the charge can in any way be substantiated ; the flies only 

 a small proportion of their total of over three thousand ; 

 and even the Hymenoptera, which contain most of all, 

 probably not much more than an eighth of their four 

 thousand or upwards. Hence it appears that, were it not 



