NOVEMBEB 2, 1891.] 



KNOWLEDGE 



.203 



chrysalis condition, and thus the latter does not itself 

 reach maturity, but perishes while still a chrysalis, 

 through the development and exit of the parasite. Here 

 the very fact of the host's being in a quiescent condition, 

 and taking no food, is the means of sounding its own 

 death knell, the parasite absorbing its vital tissues while 

 it has no power of repair ; the parasite is complete master 

 of the situation, and, in consequence, it is the rarest thing 

 imaginable for the host to straggle on to maturity. But 

 with such an insect as the Earwig the case is different. 

 Here we have an insect which has no quiescent pupa 

 stage, but continues to take food throughout life, thereby 

 to some extent perpetually neutralizing the effect of the 

 parasite's attacks ; and it is hardly surprising, therefore, 

 that in such a case the maturation of the parasite should 

 be delayed till much later in the life of the host, and that 

 the latter should thus be able to reach maturity in safety. 

 As a factor in the perpetuation of its race, however, it 

 would probably be just as devoid of influence as if it had 

 died in pupahood, as the parasite would probably subsist 

 at the expense of its reproductive organs, and thus render 

 it barren. The exit of the parasite, under such circum- 

 stances, would be an interesting event to witness, and one 

 would be glad to know the precise point at which it 

 escapes, as well as the means by which it bursts through, 

 for the skin of the perfect Earwig is much harder and 

 tougher than it is during the larval and pupal stages, and 

 the parasite is therefore much more effectually imprisoned. 

 Besides these insect parasites, a Filaria, or thread- worm, 

 has been discovered infesting the Common Earwig, as well 

 as a (rreiiarind, a creature of much simpler organization 

 even than the thread-worm. 



The systematic position of Earwigs has been a matter of 

 considerable controversy ; they constitute a very compact 

 family — the Fni-jioilidic — and were placed by Liimc in the 

 order Coleoptera, or beetles. In some respects they cer- 

 tainly do exhibit a tolerably close resemblance to one 

 particular group of this order, viz. the rove-beetles, a set 

 of carrion and dung-feeders which are technically called 

 Brachelytra. These are beetles ot narrow elongate body, 

 with very short wing-covers, so that the greater part of 

 the abdomen is exposed, instead of being, as is generally 

 the case, concealed beneath the overarching elytra, or 

 wing-covers. It was this small size of the flying apparatus 

 which suggested the name of the group, Brachelytra being 

 Greek for " short elytra." Some of the larger species of 

 this group (Fig. 6) are about the size 

 of Earwigs, and in consequence of their 

 elongate form and short elytra are 

 very generally mistaken for them, the 

 resemblance being sometimes height- 

 ened by the presence of short, pointed, 

 projecting organs at the end of the body 

 yfT', I ;"f\ in the position of the true Earwig's 



•/ Jfll^Sk V forceps. But the resemblance is after 

 "^ all only a superficial one. No true 



projecting funrps are ever developed 

 in the rove-beetles ; their wings are 

 dift'erently veined and differently folded 

 from those of Eai-wigs, and lastly, and 

 most important of all, the life-liistories 

 of the two groups are utterly unlike, 

 for the rove-beetles pass into a qui- 

 escent chrysalis stage before becoming 

 perfect insects, which is never the case 

 with Earwigs. By later systonuitists 

 the Earwigs were removed from tlie 

 Coleoptera and put into the Orthoptera, 

 amongst the cockroaches, crickets, grasshoppers, and 



Via. 6.- Philon- 

 fhus reneux, a Ruve- 

 Bcotle, aomcHiufs 

 mistaken for an 

 Karvvip. Maiinilieil 

 tlirt'i' (lianu'tiTs. 



locusts, forming, however, a distinct section of the order. 

 In the nature of their mouth organs and the style of their 

 metamorphosis they do indeed resemble these insects, yet 

 they are so peculiar, in the matter of the wings, that their 

 location with the Orthoptera did not satisfy all naturalists ; 

 consequently Kirby in 1823 removed them and made them 

 into a separate order by themselves, under the name 

 Dermaptera, an unfortunate piece of nomenclature, since 

 this term had previously been adopted as the name of the 

 whole order which is now called Orthoptera. Westwood 

 therefore proposed to replace the name Dermaptera by 

 Euplexoptera (well-folded wings), in allusion to the com- 

 plicated system of wing-folding which distinguishes Ear- 

 wigs ; but the pendulum has again swung round in the 

 opposite direction, and they are now again grouped, at 

 least by professed entomologists, in the order Orthoptera. 



We may conclude with a brief reference to the peculi- 

 arities of the popular names of these well-known pests. 

 It is remarkable that in almost all the languages of Europe 

 they are known by names which have some connection 

 with the word " ear." It is always the ear " wonn," 

 " borer," " piercer," "twister," or something of that sort, 

 names which obviously reflect the vulgar and wide-spread 

 superstition that the Earwig cree^Js into the human ear 

 and causes death by effecting thence an entrance into 

 the brain. It is curious that so manifestly absurd an idea 

 should ever have gained such wide credence — so wide 

 indeed as to have been incoi-porated into the traditional 

 lore of all the mo.st cinlized nations of the world — and 

 still more so that it should even yet show strong signs of 

 vitality. Such a notion of coarse explains the popular 

 prejudice against the Earwig, which indeed is not an insect 

 that has ever succeeded in inspiring either admiration or 

 respect ; on the other hand, superstitious fear, hatred, or 

 contempt have generally been the feelings with which 

 it has been regarded, and even its name was once 

 used as a scornful epithet, a synonym for an " inquisitive 

 informer " — no doubt in allusion to its habit of poking 

 its head into corners. 



THE MUSHROOM. 



By J. Pentland Smith, M.A., B.Sc, Ac. 

 [Lecturer on Botiiny, The Horticultural CoUeijc, Suanleij.) 



DURING the months of September and October, 

 especially if the air be moist and warm, in%-iting- 

 looking patches of white-capped ^Mushrooms 

 spring up in the green grass fields. Some are small 

 like round white buttons ; others are large and 

 have the appearance of a plate supported on a stalk. These 

 larger ones are much darker in colour than their diminutive 

 neighbours. They grow with great rapidity. I have 

 gathered Mushrooms one morning, leaving the ground 

 destitute of a vestige of them, and two mornings afterwards 

 an abundant crop has presented itself on the same spot. 



The common Mushroom is a member of a very large 

 genus — the genus Ai/tiricu^. It consists of some hundreds 

 of species, and has been broken up into a number of sub- 

 genera, and to one of these, I'xdtliotd, the common 

 Mushroom belongs. Its botanical name is Aiiaricus 

 (I'xdllidtd) cdm/icxlris. 



The stalk, technically called the stipe, which is so 

 evident in older specimens, is cylindrical in shape, and in 

 colour generally white. The disc which it supports is 

 termed the I'itiux. Its colour is variable, whitish and 

 flaky on its upper surface, as a rule, but at limos brown 

 and scaly. Alteration of situation affects it in this way, as 

 is the case with many other plants. 



