COLEOPTERA 509 



the wini^s have been examined or not. The sentence "wind's not reduced" indicates, 

 in the case of each species, that one specimen has been examined, except in the case of 

 A. subbasalis, where (as is stated) fi\-e were found to have full-sized win^s. 



Passing- to a consideration of the wing-reduction more in detail. In the original 

 type specimen of A. loiigipcs the wings have been found to be greatly reduced, but their 

 exact nature could not be determined ; the same was found to be the case in one of the 

 two specimens of A. longipcs \'ar. Iialcakalac. Two specimens of A. siibalatiis from 

 Molokai are in the same case. The type oi A. sitbalatits (from Lanai) is the only one 

 in which the reduced wing has been seen undamaged. The five specimens examined 

 for this character are thus all accounted for. 



The wing of the type specimen of A. siibalatus is shown in PI. XV. fig. 26 : the 

 line a at the side represents the length of the elytron to the same scale. It is thus seen 

 that the wing is only about f the length of the elytron. Fig. 6, drawn on a very much 

 smaller scale, shows the proportionate lengths of wing to elytron in one of the species 

 with full-sized wings. A. kauaiensis ; the wing is a little over twice the length of the 

 elytron. The wing of A. subalatus is ot course not folded ; the curious shape of it in 

 the anal area, as shown in the figure, is almost certainly due to a doubling under of the 

 anal part ; the real shape of the wing in this region being roughly indicated by the 

 dotted line. When the elytra are closed, the specimens have nothing in their appearance 

 which would lead one to suppose that their wings are reduced ; the elytra are just as 

 convex as those of species with full-sized wings. Also, the space under the elytra, in 

 \vhich the species with full-sized wings fold and pack those organs, seems to be pro- 

 portionately just as large in the reduced-winged species. The elytra of specimens with 

 reduced wings are in no case soldered together. 



It appears that reduction of wings in the Histeridae is a subject which has not 

 previously been investigated. Since, therefore, the condition of these organs in Histeridae 

 from other parts of the world is not known, no importance can be attached to the fact 

 that these species with reduced wings are insular species. 



Note. Descriptive terms. In all the Hawaiian species of Bacanius and Acritus, 

 the prosternum has two more or less raised ridges on either side. I have followed the 

 usual custom in terming these "striae." The part of the prosternum between the inner 

 pair (PI. XV. fig. 23, a) is termed the " keel." In Latin diagnoses the term "prosternum" 

 refers almost exclusively to this keel-area. When prosternal striae are mentioned, only 

 the inner pair (fig. 23, a) are meant; the outer pair (fig. 23, b), on the sloping sides of 

 the prosternum, are not made use of for systematic purposes. The marginal line of the 

 mesosternum, and the diverging lines on the metasternum continuous therewith, and 

 also the diverging lines on the first abdominal segment, are also called "striae": they 

 have almost always the nature of sunk grooves. 



Measurements. The length measurements in no case include the length of 

 the head. 



