| OCR Text |
Show 424 MR. A. D. MICHAEL ON ACARINA FROM ALGERIA. [June 3, Cephalothorax.-The plate on the dorsum of the rostrum is not carried nearly so far forward as in C. echinipes; it allows almost the whole of the palpus to be seen from the dorsal aspect projecting beyond the rostrum. The palpi are very large and are dark and chitinized, the penultimate joint very large, the ultimate provided with a strong claw or spine, the palpus also bears several large spatulate hairs ; the median portion of the rostral plate is depressed and marked with several parallel, straight, longitudinal lines. This central portion is bordered by a large raised ridge or roll on each side; the ridges are narrow anteriorly, where they nearly meet, and gradually thicken and become more separated towards their posterior ends, which are suddenly thickened and turned inward. These ridges are thickly set with stout, very curved, opaque white hairs which are extremely conspicuous. The chitinizing of the rest of the body hardly assumes the form of distinct plates. The median portion of the cephalothorax behind the rostrum is raised, forming three large rough lobes. There are two long spatulate hairs on each side of each lobe, thus forming two longitudinal lines ; they are much longer and less spatulate than those on C. echinipes. All round these lobes is a deep depressed trench, showing the striated skin but little chitinized; outside this laterally is a raised chitinized margin composed of three lobes on each side, and a fourth lobe continues on to the posterior margin of the cephalothorax; these lobes all bear spatulate hairs similar in character to those on the central lobes. The posterior margin is bordered with hairs corresponding to those described below as bordering the abdomen. The eyes are two on each side, placed as in C. echinipes, but rather more projecting. Legs very similar to those of C. echinipes, but the spines on the femora of the first pair are more curved. The claws are didactyle, but the two claws of each pair are very unequal, one claw being strong, thick at the base, and slightly brown ; the other very small and short, on some of the legs quite rudimentary. Abdomen (if this be really the division of the body) only projecting a comparatively short distance behind the cephalothorax, and decidedly lower in level, so that the hairs on the hind margin of the cephalothorax stand free above it. The hind margin is divided into two flat lobes, being thus indented at the median line; it is bordered by a close line of large spatulate hairs, of which some are markedly larger than others. The arrangement of the sizes is definite: starting from the median line we find, on each side, first three small hairs, then a large one, then two small, then one large, and then two more small. All these hairs, and indeed all the spatulate hairs, both on the body and legs, are opaque white, giving the creature a very singular and conspicuous appearance. I was only able to obtain one specimen of this species, which was found in moss in the forest of Ain Beida, near Algiers. I doubt if it be quite mature. I therefore thought at first that it might possibly be some young form of C. echinipes ; but Professor Berlese, of Florence, has been kind enough to lend m e all his specimens of that |
