The sex chromosomes are the largest chromosomes and constitute 30% of the total length of the diploid set in females and about 25% in males.[18] [18] Slime mold (Dictyostelium discoideum) 12 [19] Cucumber (Cucumis sativus) 14 [20] Tasmanian devil (Sarcophilus harrisii) 14 Rye (Secale cereale) 14 [21] Pea (Pisum sativum) 14 [21] Barley (Hordeum vulgare) 14 [22] Aloe vera 14 The diploid chromosome number is 2n = 14 with four pair of long acrocentric chromosomes ranging from 14.4 μm to 17.9 μm and three pair of short sub metacentric chromosomes ranging from 4.6 μm to 5.4 μm.[23] [23] Koala (Phascolarctos cinereus) 16 Kangaroo 16 This includes several members of genus Macropus, but not the red kangaroo (M. rufus, 20) [24] Schistosoma mansoni 16 2n=16. 7 autosomal pairs and ZW sex-determination pair.[25] [25] Welsh onion (Allium Fistulosum) 16 [26] Garlic (Allium sativum) 16 [26] Itch mite (Sarcoptes scabiei) 17/18 According to the observation of embryonic cells of egg, chromosome number of the itch mite is either 17 or 18.