The number of eggs in a clutch is two, three, or rarely four. The first two weeks in May find almost all the San Lucas Woodpeckers at the peak of laying. After the middle of the month nests with young may be expected. The parent bird will ordinarily flush, especially if the cardón be tapped, but it is not very nervous about its home. It is too busy with family duties to waste much attention on strangers. The eggs are similar to those of the other subspecies. Bancroft (1930) gives the average measurements of 23 eggs as 22.9 by 18.1 millimeters. The measurements of 10 other eggs average 21.30 by 16.61 millimeters; the eggs, in this series, showing the four extremes measure =24.40= by 18.70, 23.70 by =18.80=, =19.50= by 16.80, and 21.43 by =15.42= millimeters. DRYOBATES SCALARIS CACTOPHILUS Oberholser CACTUS WOODPECKER HABITS The ladder-backed woodpeckers are quite widely distributed in the Southwestern United States and in nearly all Mexico and in British Honduras, chiefly in the Lower Austral and Tropical Zones. When Dr. Harry C. Oberholser (1911b) wrote his revision of this group, he split the species _Dryobates scalaris_ into 15 subspecies, 9 of which he described and named as new subspecies. Only two of these subspecies are found within the limits of the United States, and only two in Baja California, giving us four on our Check-List. The name _Dryobates scalaris bairdi_, which was for a long time used to designate the ladder-backed woodpeckers of the United States, was restricted by Oberholser to a Mexican form. He gave as the characters of _cactophilus_, “much like _Dryobates scalaris eremicus_, but smaller, particularly the tail and bill; lower surface lighter, laterally almost always _streaked_ with black; upper parts lighter--the black bars on back and scapulars narrower; wing-quills with larger spots and broader bars of white; outer long rectrices with exterior webs barred throughout with black; black bars on posterior lower surface narrower.” Ridgway (1914) compares it with _symplectus_, the Texas bird, as “slightly larger, and with black bars on back, etc., decidedly broader.” The cactus woodpecker ranges, according to the 1931 A. O. U. Check-List, from “central western Texas through New Mexico and Arizona to extreme northeastern Lower California and southeastern California, north to extreme southern Nevada and southwestern Utah, and south to northern Durango.” It frequents the deserts, or the borders of the deserts, and the lower slopes of the mountains in the Sonoran Zone, a hot, dry region where there are no trees of any size and where this is about the only species of woodpecker found. We never found it in the giant-cactus, or saguaro, region, where it seemed to be replaced by the noisy Gila woodpecker and Mearns’s gilded flicker. W. Leon Dawson (1923) says: