A fifth survey of malaria and anopheles in New Mexico is described. This survey was made in the summer of 1938. The more outstanding findings were made in the Pecos Valley in the southeastern part of the state. A. maculipennis was found for the first time in Pecos Valley. The probabilities are that this species has been recently introduced. It occurs in large numbers near a Civilian Conservation Corps camp at Rattlesnake Springs, where it is certainly a menace to the health of the men in this camp.
An extended survey indicated that maculipennis has not as yet spread far from the focus at Rattlesnake Springs.
An examination of blood specimens of nearly 100 children indicates that in this region there is at present little or no transmission of malaria due to punctipennis or pseudopunctipennis. This finding confirms the testimony of health authorities that there is no malaria in the Pecos Valley except that introduced from outside.
Species of Anopheles from various parts of the state were compared with respect to the variability of certain characteristics: wings, male terminalia, eggs, the pecten of the eighth abdominal segment of the larva, and the spermathecae.
A. crucians was found in a brackish swamp near Artesia, southeastern New Mexico. This is the first finding of this species in the state, perhaps in the whole Rocky Mountain region.