In the first cytogenetic study of the recently proposed family Myerslopiidae the male karyotype of Mapuchea chilensis (Nielson, 1996) was analyzed using conventional chromosome staining, AgNOR- and C-bandings, and fluorescence in situ hybridization (FISH) with 18S rDNA and (TTAGG)n telomeric probes. A karyotype of 2n = 16 + XY, NOR on a medium-sized pair of autosomes, subterminal location of C-heterochromatin, and presence of (TTAGG)n telomeric sequence were determined. Additionally, the male internal reproductive system was studied.

Male karyotypes of Elasmotropis testacea (Herrich-Schaeffer, 1835), Tingis cardui (Linnaeus, 1758), T. crispata (Herrich-Schaeffer, 1838), and Agramma femorale Thomson, 1871 (Heteroptera, Cimicomorpha, Tingidae) were analyzed using conventional chromosome staining and FISH with 18S rDNA and (TTAGG)n telomeric probes. The FISH technique was applied for the first time in the Tingidae. In spite of the fact that all species showed the same chromosome number (2n = 12 + XY), they have significant differences in the number and position of rDNA loci. FISH with the classical insect (TTAGG)n probe produced no signals on chromosomes suggesting telomeres in lace bugs to be of some other molecular composition. Tingidae share absence of the (TTAGG)n telomeric sequence with all so far studied taxa of the advanced true bug infraorders Cimicomorpha and Pentatomomorpha.

The lace bug family Tingidae comprises more than 2600 described species in 318 genera that are classified into the subfamilies Tinginae (about 2500 species and 300 genera), Cantacaderinae, and Vianadinae. We provide data on karyotypes of 16 species belonging to 10 genera of the tribes Tingini and Acalyptaini (Tinginae) studied using conventional chromosome staining and FISH. The species of Tingini possess 2n = 12A + XY, whereas those of Acalyptaini have 2n = 12A + X(0). FISH for 18S rDNA revealed hybridization signals on one of the medium-sized bivalents in species of both tribes. FISH with a telomeric probe TTAGG produced no signals in any species. In addition, we provide a list of all data obtained to date on Tingidae karyotypes, which includes 60 species from 22 genera of Tinginae. The subfamily is highly conservative in relation to the number and size of autosomes, whereas it shows diversity in the number and chromosomal distribution of the rDNA arrays, which may be located either on a pair of autosomes (the predominant and supposedly ancestral pattern), on one or both sex chromosomes, or on an autosome pair and the X. The absence of the “insect” telomeric sequence TTAGG in all species implies that Tinginae have some other, yet unknown, telomere organization.

The karyotypes of 10 species from 9 genera of the family Tingidae (Hemiptera, Heteroptera, Cimicomorpha) are described and illustrated for the first time. These species are: Agrammaatricapillum (Spinola, 1837), Catoplatuscarthusianus (Goeze, 1778), Dictylaplatyoma (Fieber, 1861), Lasiacanthahermani Vásárhelyi, 1977, Oncochilasimplex (Herrich-Schaeffer, 1830), Tingis (Neolasiotropis) pilosa Hummel, 1825, and T. (Tropidocheila) reticulata Herrich-Schaeffer, 1835, all with 2n = 12A + XY, as well as Acalyptamarginata (Wolff, 1804), Derephysia (Paraderephysia) longispina Golub, 1974, and Dictyonotastrichnocera Fieber, 1844, all with 2n = 12A + X(0). Moreover, genera Catoplatus Spinola, 1837, Derephysia Spinola, 1837, and Oncochila (Herrich-Schaeffer, 1830) were explored cytogenetically for the first time. Much as all other hitherto studied lace bugs, the species studied here have 12 autosomes but differ in their sex chromosome systems. The ribosomal clusters were localized on male meiotic cells of all ten species already mentioned and, additionally, in Acalyptacarinata Panzer, 1806 known to have 2n = 12A + X (Grozeva and Nokkala 2001) by fluorescence in situ hybridization (FISH) using a PCR amplified 18S rDNA fragment as a probe. In all cases, rDNA loci were located interstitially on a pair of autosomes. Furthermore, two species possessed some additional rDNA clusters. Thus, Acalyptamarginata showed clearly defined interstitial clusters on one more pair of autosomes, whereas Derephysialongispina had a terminal cluster on the X-chromosome. FISH performed with the telomeric (TTAGG)_n probe did not reveal labelling in chromosomes of any species studied. Hence, the results obtained provide additional evidence for the karyotype conservatism, at least regarding the number of autosomes, for variation in chromosomal distribution of rDNA loci between species and for the lack of the ancestral insect telomeric sequence TTAGG in lace bugs. Preliminary taxonomic comments are made basing on some cytogenetic evidence.

Karyotypes of eight Psocoptera species are reported for the first time. In Valenzuela oyamai (Enderlein, 1906) (Caeciliusidae), Peripsocus golubae Lienhard, 200