18 ILLINOIS BIOLOGICAL MONOGRAPHS [412 



shown in figures 870-372, plate XVI, which accord with those of Cicin- 

 dela. In Megacephala klugi we find a curious dark spot in the position 

 of the cross veins between the subcosta and the ramus which corres- 

 ponds to the condition that Tower (1906) has called attention to in the 

 Coleoptera, Lepidoptera, etc., but it is not of frequent enough occur- 

 rence to be significant. I know of no color patterns in the Palaeoman- 

 tichoridae or the Neomantichoridae, both the wings are rudimentary 

 and in the latter the eyes are much reduced and they are in some cases 

 light avoiding. 



In Platychila pallida we have only a very slight pigmentation any- 

 where on the body; the wings are reduced to a rudiment that is barely 

 distinguishable and the elytron is pigmented only in a small area lying 

 in its anterior two thirds and along its inner side. There is no develop- 

 ment of spaces in the secondary cuticula sufficient to make the chitin 

 opaque and yellow. 



In the Dytiscidae, Carabidae, and Haliplidae, the chitinous columns 

 are arranged in definite rows and likewise in many cases the hairs and 

 glands. The center of these chitinous columns, or better the primary 

 cuticula over the chitinous columns, is last to lose its pigment; accord- 

 ingly one may find a line of pigmented spots lying in rows, often two 

 rows, between the tracheae, for example as is shown in the Bembidium 

 versicolor Lee. (Fig. 35). The row of chitinous columns break across 

 the white markings and in some of our common Haliplidae, for example, 

 the chitinous columns are so arranged and the centers are associated 

 with the openings of glands, the cells of which have caused the column 

 to be cut half in two. 



To find what are the conditions of the tracheal structures in other 

 Adephaga I made an examination of a number of forms in the Dytis- 

 cidae, Carabidae, and Haliplidae, (Figs. 34 to 41, PI. IV). Omophron 

 shows all six tracheae and three cross bands which do not appear to be 

 related to the tracheae. Bembidium versicolor shows only five tracheae, 

 but the unpigmented areas are in the lines of the tracheae and also 

 between them. Nebria complanata (Fig. 37, Europe) shows the tra- 

 cheae in the lines of pigmentation as well as a suggestion of the double 

 banding shown in the Dytiscidae. The Dytiscid (Hydacticus stagnalis, 

 Fig. 38) shows all of the six tracheae and a light line both between and 

 directly above them. Figure 39 (Laccophilus maculosus) shows suggest- 

 ions of cross bands and double stripes. Agabus teniolatus (Fig. 40) 

 shows the tracheae within the lines of the unpigmented cuticula. Hydro- 

 porus undulatus (Fig. 39) has the cross bands and the tracheae appar- 

 ently between the spots. (Compare with figures 2 to 25, plates I to III). 



From the studies preceding, especially the last, it is observed that 

 there is no constant relation between the tracheae and the distribution 



