468 THE ENTOMOLOGIST. 



apterous insects, or between metabolous and ametabolous 

 insects, the step will involve them in perplexities and 

 labyrinths, from which they may hopelessly seek to 

 extricate themselves. The metamorphosis of the bed-bug, 

 like that of Haematopinus, is an oft-repeated ecdysis without 

 change of form, and without the attainment of additional 

 organs of locomotion. The absence of wings in insects is 

 generally accompanied by an absence also of compound eyes : 

 this is always the case in the female Psychidae (Lepidoptera), 

 in the Pulicidse(Diptera), the female Agaonidaj (Hymenoplera; 

 see the figures and description of Apocrypta and Sycocrypta, 

 Entom. V. 399), and the female Stylopidaj (Coleoptera), and, 

 therefore, the exhibition of similar characters in the Nirmidae 

 and Pediculidae cannot logically be cited as an argument 

 against the admission of these groups respectively with the 

 Orthoptera and Hemiptera. 



The simultaneous degradation of widely different organs in 

 insects is a subject worthy the closest investigation. As 

 might be expected, the thoracic segments are wonderfully 

 altered when wings are absent; the competent parts are no 

 longer to be recognized. We have a daily example of this in 

 the winged and wingless ants, and strangely enough the 

 winged ants are constantly in the habit of self-mutilation : 

 they take off their own wings, as if to show us the difference 

 in the structure of a thorax naturally winged and a thorax 

 naturally wingless ; but that this should be correlative to a 

 similar degradation in the organs of vision may possibly seem 

 by no means requisite ; still such is the case, and the reason 

 is sufficiently obvious. A creature confined in a case (like 

 the female Psyche), or procuring food in the dark, buried in 

 the substance of a fig (like Sycocrypta), or in the body of a bee 

 (like the female Stylops), or crawling by means of prehensile 

 claws on the skins of beasts and birds, or climbing among 

 their hairs and feathers (like the Pediculidae and Nirmidae), 

 certainly requires no extensive powers of vision ; and the 

 same law which denied them aerial locomotion simultaneously 

 deprived them of those guiding faculties which are necessary 

 for its government and control. Cave beetles and ants'-nest 

 beetles offer striking instances of this. Degradation in these 

 humble forms of life goes still further, for the female of 

 Stylops and Psyche have neither eyes, ocelli, palpi, antennae, 



