Aquino Perez, G., García Velásquez, A., Corona, T., & Bárcenas Ortega, N.M. 1994 Estudio cromosomico de cuatro especies de "cochinillas del nopal" Dactylopius spp. (Homoptera: Dactylopiidae). [Chromosome study of four species of prickly pear cochineal Dactylopius spp. (Homoptera: Dactylopiidae).]. Agrociencia serie Fitociencia 5(1): 7-23.

Notes: The reproductive system, karyotype and meiotic sequences of four species of cochineal insects (Dactylopius spp.), three wild Dactylopius sp1, D. confusus and Dactylopius sp.2) and one cultivated D. coccus were studied. Testis and ovaries were stained with lacto-acetic-orcein 2%. Chromosome preparations were made using the squash technique. The reproductive system is sexual with both sexes diploid but physiologically haploid males. The chromosomes number in the wild species is 2n=10; four pairs of short and one pair of large chromosomes, the latter about three times the length of the short ones. The chromosome number of C. coccus is 2n=16; all of which are relatively short. The sum of the length of the four shortest chromosomes of D. coccus is similar to the length of the longest chromosome of the wild species. The length of the chromosome complement is similar in the four species. The meiotic sequence observed in these four cochineal species is of the Comstockiella type.